diff --git a/lib/Adaptor.js b/lib/Adaptor.js
index 881139b..b979d21 100644
--- a/lib/Adaptor.js
+++ b/lib/Adaptor.js
@@ -3,7 +3,7 @@
 Object.defineProperty(exports, "__esModule", {
   value: true
 });
-exports.lastReferenceValue = exports.dataValue = exports.dataPath = exports.merge = exports.sourceValue = exports.fields = exports.field = undefined;
+exports.lastReferenceValue = exports.dataValue = exports.dataPath = exports.each = exports.merge = exports.sourceValue = exports.fields = exports.field = undefined;
 
 var _extends = Object.assign || function (target) { for (var i = 1; i < arguments.length; i++) { var source = arguments[i]; for (var key in source) { if (Object.prototype.hasOwnProperty.call(source, key)) { target[key] = source[key]; } } } return target; };
 
@@ -41,6 +41,12 @@ Object.defineProperty(exports, 'merge', {
     return _languageCommon.merge;
   }
 });
+Object.defineProperty(exports, 'each', {
+  enumerable: true,
+  get: function get() {
+    return _languageCommon.each;
+  }
+});
 Object.defineProperty(exports, 'dataPath', {
   enumerable: true,
   get: function get() {
@@ -121,9 +127,16 @@ function event(eventData) {
     console.log("Posting event:");
     console.log(body);
 
-    return (0, _Client.post)({ username: username, password: password, body: body, url: url }).then(function (result) {
+    return (0, _Client.post)({
+      username: username,
+      password: password,
+      body: body,
+      url: url
+    }).then(function (result) {
       console.log("Success:", result);
-      return _extends({}, state, { references: [result].concat(_toConsumableArray(state.references)) });
+      return _extends({}, state, {
+        references: [result].concat(_toConsumableArray(state.references))
+      });
     });
   };
 }
@@ -154,15 +167,36 @@ function dataValueSet(data) {
     console.log("Posting data value set:");
     console.log(body);
 
-    return (0, _Client.post)({ username: username, password: password, body: body, url: url }).then(function (result) {
+    return (0, _Client.post)({
+      username: username,
+      password: password,
+      body: body,
+      url: url
+    }).then(function (result) {
       console.log("Success:", result);
-      return _extends({}, state, { references: [result].concat(_toConsumableArray(state.references)) });
+      return _extends({}, state, {
+        references: [result].concat(_toConsumableArray(state.references))
+      });
     });
   };
 }
 
+/**
+ * Create a "dataElement" pairing for DHIS2.
+ * @example
+ * execute(
+ *   dataElement(key, value)
+ * )(state)
+ * @constructor
+ * @param {object} key - Payload data for the Data Element key
+ * @param {object} value - Payload data for the Data Element value
+ * @returns {Operation}
+ */
 function dataElement(key, value) {
-  return { "dataElement": key, "value": value };
+  return {
+    "dataElement": key,
+    "value": value
+  };
 }
 
 /**
@@ -192,9 +226,16 @@ function createTEI(data) {
     console.log("Posting tracked entity instance data:");
     console.log(body);
 
-    return (0, _Client.post)({ username: username, password: password, body: body, url: url }).then(function (result) {
+    return (0, _Client.post)({
+      username: username,
+      password: password,
+      body: body,
+      url: url
+    }).then(function (result) {
       console.log("Success:", result);
-      return _extends({}, state, { references: [result].concat(_toConsumableArray(state.references)) });
+      return _extends({}, state, {
+        references: [result].concat(_toConsumableArray(state.references))
+      });
     });
   };
 }
@@ -203,13 +244,14 @@ function createTEI(data) {
  * Update existing Tracked Entity Instances
  * @example
  * execute(
- *   updateTEI(data)
+ *   updateTEI(tei, data)
  * )(state)
  * @constructor
- * @param {object} data - Payload data for updating tracked entity instance(s)
+ * @param {object} tei - Payload data for the TEI to be updated
+ * @param {object} data - Payload data for updating a TEI
  * @returns {Operation}
  */
-function updateTEI(data) {
+function updateTEI(tei, data) {
 
   return function (state) {
     var body = (0, _languageCommon.expandReferences)(data)(state);
@@ -220,19 +262,35 @@ function updateTEI(data) {
     var apiUrl = _state$configuration4.apiUrl;
 
 
-    var url = (0, _url.resolve)(apiUrl + '/', 'api/trackedEntityInstances');
+    var url = apiUrl.concat('/api/trackedEntityInstances/' + tei);
 
-    console.log("Posting tracked entity instance data:");
+    console.log('Updating tracked entity instance ' + tei + ' with data:');
     console.log(body);
 
-    return (0, _Client.post)({ username: username, password: password, body: body, url: url }).then(function (result) {
+    return (0, _Client.put)({
+      username: username,
+      password: password,
+      body: body,
+      url: url
+    }).then(function (result) {
       console.log("Success:", result);
-      return _extends({}, state, { references: [result].concat(_toConsumableArray(state.references)) });
+      return _extends({}, state, {
+        references: [result].concat(_toConsumableArray(state.references))
+      });
     });
   };
 }
 
-// Create and enroll TrackedEntityInstances
+// /**
+//  * Create and enroll TrackedEntityInstances
+//  * @example
+//  * execute(
+//  *   createEnrollTEI(te, orgUnit, attributes, enrollments)
+//  * )(state)
+//  * @constructor
+//  * @param {object} enrollmentData - Payload data for new enrollment
+//  * @returns {Operation}
+//  */
 // export function upsertEnroll(upsertData) {
 //
 //   return state => {
@@ -254,11 +312,21 @@ function updateTEI(data) {
 //   }
 // }
 
-// Enroll a tracked entity instance in a program
-function enroll(enrollmentData) {
+/**
+ * Enroll a tracked entity instance in a program
+ * @example
+ * execute(
+ *   enroll(enrollmentData)
+ * )(state)
+ * @constructor
+ * @param {object} enrollmentData - Payload data for new enrollment
+ * @returns {Operation}
+ */
+function enroll(tei, enrollmentData) {
 
   return function (state) {
     var body = (0, _languageCommon.expandReferences)(enrollmentData)(state);
+    body["trackedEntityInstance"] = tei;
 
     var _state$configuration5 = state.configuration;
     var username = _state$configuration5.username;
@@ -268,12 +336,19 @@ function enroll(enrollmentData) {
 
     var url = (0, _url.resolve)(apiUrl + '/', 'api/enrollments');
 
-    console.log("Enrolling tracked entity instance:");
+    console.log("Enrolling tracked entity instance with data:");
     console.log(body);
 
-    return (0, _Client.post)({ username: username, password: password, body: body, url: url }).then(function (result) {
+    return (0, _Client.post)({
+      username: username,
+      password: password,
+      body: body,
+      url: url
+    }).then(function (result) {
       console.log("Success:", result);
-      return _extends({}, state, { references: [result].concat(_toConsumableArray(state.references)) });
+      return _extends({}, state, {
+        references: [result].concat(_toConsumableArray(state.references))
+      });
     });
   };
 }
diff --git a/lib/Client.js b/lib/Client.js
index 701b868..d9d2d4d 100644
--- a/lib/Client.js
+++ b/lib/Client.js
@@ -4,6 +4,7 @@ Object.defineProperty(exports, "__esModule", {
   value: true
 });
 exports.post = post;
+exports.put = put;
 
 var _superagent = require('superagent');
 
@@ -22,7 +23,22 @@ function post(_ref) {
       if (!!error || !res.ok) {
         reject(error);
       }
+      resolve(res);
+    });
+  });
+}
+
+function put(_ref2) {
+  var username = _ref2.username;
+  var password = _ref2.password;
+  var body = _ref2.body;
+  var url = _ref2.url;
 
+  return new Promise(function (resolve, reject) {
+    _superagent2.default.put(url).type('json').accept('json').auth(username, password).send(JSON.stringify(body)).end(function (error, res) {
+      if (!!error || !res.ok) {
+        reject(error);
+      }
       resolve(res);
     });
   });
diff --git a/src/Adaptor.js b/src/Adaptor.js
index 0df902c..0458c70 100644
--- a/src/Adaptor.js
+++ b/src/Adaptor.js
@@ -1,6 +1,14 @@
-import { execute as commonExecute, expandReferences } from 'language-common';
-import { post } from './Client';
-import { resolve as resolveUrl } from 'url';
+import {
+  execute as commonExecute,
+  expandReferences
+} from 'language-common';
+import {
+  post,
+  put
+} from './Client';
+import {
+  resolve as resolveUrl
+} from 'url';
 
 /** @module Adaptor */
 
@@ -23,7 +31,9 @@ export function execute(...operations) {
   }
 
   return state => {
-    return commonExecute(...operations)({ ...initialState, ...state })
+    return commonExecute(...operations)({...initialState,
+      ...state
+    })
   };
 
 }
@@ -43,18 +53,29 @@ export function event(eventData) {
   return state => {
     const body = expandReferences(eventData)(state);
 
-    const { username, password, apiUrl } = state.configuration;
+    const {
+      username,
+      password,
+      apiUrl
+    } = state.configuration;
 
     const url = resolveUrl(apiUrl + '/', 'api/events')
 
     console.log("Posting event:");
     console.log(body)
 
-    return post({ username, password, body, url })
-    .then((result) => {
-      console.log("Success:", result);
-      return { ...state, references: [ result, ...state.references ] }
-    })
+    return post({
+        username,
+        password,
+        body,
+        url
+      })
+      .then((result) => {
+        console.log("Success:", result);
+        return {...state,
+          references: [result, ...state.references]
+        }
+      })
 
   }
 }
@@ -74,24 +95,49 @@ export function dataValueSet(data) {
   return state => {
     const body = expandReferences(data)(state);
 
-    const { username, password, apiUrl } = state.configuration;
+    const {
+      username,
+      password,
+      apiUrl
+    } = state.configuration;
 
     const url = resolveUrl(apiUrl + '/', 'api/dataValueSets')
 
     console.log("Posting data value set:");
     console.log(body)
 
-    return post({ username, password, body, url })
-    .then((result) => {
-      console.log("Success:", result);
-      return { ...state, references: [ result, ...state.references ] }
-    })
+    return post({
+        username,
+        password,
+        body,
+        url
+      })
+      .then((result) => {
+        console.log("Success:", result);
+        return {...state,
+          references: [result, ...state.references]
+        }
+      })
 
   }
 }
 
+/**
+ * Create a "dataElement" pairing for DHIS2.
+ * @example
+ * execute(
+ *   dataElement(key, value)
+ * )(state)
+ * @constructor
+ * @param {object} key - Payload data for the Data Element key
+ * @param {object} value - Payload data for the Data Element value
+ * @returns {Operation}
+ */
 export function dataElement(key, value) {
-  return { "dataElement": key, "value": value }
+  return {
+    "dataElement": key,
+    "value": value
+  }
 }
 
 /**
@@ -110,18 +156,29 @@ export function createTEI(data) {
 
     const body = expandReferences(data)(state);
 
-    const { username, password, apiUrl } = state.configuration;
+    const {
+      username,
+      password,
+      apiUrl
+    } = state.configuration;
 
     const url = resolveUrl(apiUrl + '/', 'api/trackedEntityInstances')
 
     console.log("Posting tracked entity instance data:");
     console.log(body)
 
-    return post({ username, password, body, url })
-    .then((result) => {
-      console.log("Success:", result);
-      return { ...state, references: [ result, ...state.references ] }
-    })
+    return post({
+        username,
+        password,
+        body,
+        url
+      })
+      .then((result) => {
+        console.log("Success:", result);
+        return {...state,
+          references: [result, ...state.references]
+        }
+      })
 
   }
 }
@@ -130,34 +187,55 @@ export function createTEI(data) {
  * Update existing Tracked Entity Instances
  * @example
  * execute(
- *   updateTEI(data)
+ *   updateTEI(tei, data)
  * )(state)
  * @constructor
- * @param {object} data - Payload data for updating tracked entity instance(s)
+ * @param {object} tei - Payload data for the TEI to be updated
+ * @param {object} data - Payload data for updating a TEI
  * @returns {Operation}
  */
-export function updateTEI(data) {
+export function updateTEI(tei, data) {
 
   return state => {
     const body = expandReferences(data)(state);
 
-    const { username, password, apiUrl } = state.configuration;
+    const {
+      username,
+      password,
+      apiUrl
+    } = state.configuration;
 
-    const url = resolveUrl(apiUrl + '/', 'api/trackedEntityInstances')
+    const url = apiUrl.concat(`/api/trackedEntityInstances/${tei}`)
 
-    console.log("Posting tracked entity instance data:");
+    console.log(`Updating tracked entity instance ${tei} with data:`);
     console.log(body)
 
-    return post({ username, password, body, url })
-    .then((result) => {
-      console.log("Success:", result);
-      return { ...state, references: [ result, ...state.references ] }
-    })
+    return put({
+        username,
+        password,
+        body,
+        url
+      })
+      .then((result) => {
+        console.log("Success:", result);
+        return {...state,
+          references: [result, ...state.references]
+        }
+      })
 
   }
 }
 
-// Create and enroll TrackedEntityInstances
+// /**
+//  * Create and enroll TrackedEntityInstances
+//  * @example
+//  * execute(
+//  *   createEnrollTEI(te, orgUnit, attributes, enrollments)
+//  * )(state)
+//  * @constructor
+//  * @param {object} enrollmentData - Payload data for new enrollment
+//  * @returns {Operation}
+//  */
 // export function upsertEnroll(upsertData) {
 //
 //   return state => {
@@ -179,30 +257,57 @@ export function updateTEI(data) {
 //   }
 // }
 
-
-// Enroll a tracked entity instance in a program
-export function enroll(enrollmentData) {
+/**
+ * Enroll a tracked entity instance in a program
+ * @example
+ * execute(
+ *   enroll(enrollmentData)
+ * )(state)
+ * @constructor
+ * @param {object} enrollmentData - Payload data for new enrollment
+ * @returns {Operation}
+ */
+export function enroll(tei, enrollmentData) {
 
   return state => {
     const body = expandReferences(enrollmentData)(state);
+    body["trackedEntityInstance"] = tei;
 
-    const { username, password, apiUrl } = state.configuration;
+    const {
+      username,
+      password,
+      apiUrl
+    } = state.configuration;
 
     const url = resolveUrl(apiUrl + '/', 'api/enrollments')
 
-    console.log("Enrolling tracked entity instance:");
+    console.log("Enrolling tracked entity instance with data:");
     console.log(body)
 
-    return post({ username, password, body, url })
-    .then((result) => {
-      console.log("Success:", result);
-      return { ...state, references: [ result, ...state.references ] }
-    })
+    return post({
+        username,
+        password,
+        body,
+        url
+      })
+      .then((result) => {
+        console.log("Success:", result);
+        return {...state,
+          references: [result, ...state.references]
+        }
+      })
 
   }
 }
 
 export {
-  field, fields, sourceValue,
-  merge, dataPath, dataValue, lastReferenceValue
-} from 'language-common';
+  field,
+  fields,
+  sourceValue,
+  merge,
+  each,
+  dataPath,
+  dataValue,
+  lastReferenceValue
+}
+from 'language-common';
diff --git a/src/Client.js b/src/Client.js
index 6b310b0..c03907a 100644
--- a/src/Client.js
+++ b/src/Client.js
@@ -1,19 +1,43 @@
 import request from 'superagent'
 
-export function post({ username, password, body, url }) {
+export function post({
+  username,
+  password,
+  body,
+  url
+}) {
   return new Promise((resolve, reject) => {
     request.post(url)
-    .type('json')
-    .accept('json')
-    .auth(username, password)
-    .send(JSON.stringify(body))
-    .end((error, res) => {
-      if (!!error || !res.ok) {
-        reject( error )
-      }
-
-      resolve( res )
-    })
+      .type('json')
+      .accept('json')
+      .auth(username, password)
+      .send(JSON.stringify(body))
+      .end((error, res) => {
+        if (!!error || !res.ok) {
+          reject(error)
+        }
+        resolve(res)
+      })
+  })
+}
 
+export function put({
+  username,
+  password,
+  body,
+  url
+}) {
+  return new Promise((resolve, reject) => {
+    request.put(url)
+      .type('json')
+      .accept('json')
+      .auth(username, password)
+      .send(JSON.stringify(body))
+      .end((error, res) => {
+        if (!!error || !res.ok) {
+          reject(error)
+        }
+        resolve(res)
+      })
   })
 }