diff --git a/src/Voice/Bxml/Bxml.php b/src/Voice/Bxml/Bxml.php
new file mode 100644
index 0000000..6030401
--- /dev/null
+++ b/src/Voice/Bxml/Bxml.php
@@ -0,0 +1,49 @@
+<?php
+/**
+ * Bxml.php
+ *
+ * Class that represents the BXML response. Is built by adding verbs to it
+ *
+ *  * @copyright Bandwidth INC
+ */
+
+namespace BandwidthLib\Voice\Bxml;
+
+use DOMDocument;
+
+class Bxml {
+
+    /**
+     * Creates the Bxml class with an empty list of verbs
+     */
+    public function __construct() {
+        $this->verbs = array();
+    }
+    
+    /**
+     * Adds the verb to the verbs
+     *
+     * @param Verb $verb The verb to add to the list
+     */
+    public function addVerb($verb) {
+        array_push($this->verbs, $verb);
+    }
+
+    /**
+     * Converts the Response class into its BXML representation
+     *
+     * @return string The xml representation of the class
+     */
+    public function toBxml() {
+        $ssmlRegex = '/&lt;([a-zA-Z\/\/].*?)&gt;/';
+        $doc = new DOMDocument('1.0', 'UTF-8');
+        $bxmlElement = $doc->createElement("Bxml");
+
+        foreach ($this->verbs as $verb) {
+            $bxmlElement->appendChild($verb->toBxml($doc));
+        }
+
+        $doc->appendChild($bxmlElement);
+        return str_replace("\n", '', preg_replace($ssmlRegex, "<$1>", $doc->saveXML()));
+    }
+}
diff --git a/src/Voice/Controllers/APIController.php b/src/Voice/Controllers/APIController.php
index 3440f81..b55820d 100644
--- a/src/Voice/Controllers/APIController.php
+++ b/src/Voice/Controllers/APIController.php
@@ -249,6 +249,114 @@ public function getCall(
         return new ApiResponse($response->code, $response->headers, $deserializedResponse);
     }
 
+/**
+     * Replaces the bxml for an active call
+     *
+     * @param string                   $accountId TODO: type description here
+     * @param string                   $callId    TODO: type description here
+     * @param string                   $body      Valid BXML string 
+     * @return ApiResponse response from the API call
+     * @throws APIException Thrown if API call fails
+     */
+    public function modifyCallBxml(
+        $accountId,
+        $callId,
+        $body
+    ) {
+
+        //prepare query string for API call
+        $_queryBuilder = '/api/v2/accounts/{accountId}/calls/{callId}';
+
+        //process optional query parameters
+        $_queryBuilder = APIHelper::appendUrlWithTemplateParameters($_queryBuilder, array (
+            'accountId' => $accountId,
+            'callId' => $callId,
+            ));
+
+        //validate and preprocess url
+        $_queryUrl = APIHelper::cleanUrl($this->config->getBaseUri(Servers::VOICEDEFAULT) . $_queryBuilder);
+
+        //prepare headers
+        $_headers = array (
+            'user-agent'    => BaseController::USER_AGENT,
+            'content-type'  => 'application/xml; charset=utf-8'
+        );
+
+        //set HTTP basic auth parameters
+        Request::auth($this->config->getVoiceBasicAuthUserName(), $this->config->getVoiceBasicAuthPassword());
+
+        $_httpRequest = new HttpRequest(HttpMethod::POST, $_headers, $_queryUrl);
+
+        //call on-before Http callback
+        if ($this->getHttpCallBack() != null) {
+            $this->getHttpCallBack()->callOnBeforeRequest($_httpRequest);
+        }
+        // Set request timeout
+        Request::timeout($this->config->getTimeout());
+
+        // and invoke the API call request to fetch the response
+        $response = Request::post($_queryUrl, $_headers, $body);
+
+        $_httpResponse = new HttpResponse($response->code, $response->headers, $response->raw_body);
+        $_httpContext = new HttpContext($_httpRequest, $_httpResponse);
+
+        //call on-after Http callback
+        if ($this->getHttpCallBack() != null) {
+            $this->getHttpCallBack()->callOnAfterRequest($_httpContext);
+        }
+
+        //Error handling using HTTP status codes
+        if ($response->code == 400) {
+            throw new Exceptions\ApiErrorException(
+                'Something\'s not quite right... Your request is invalid. Please fix it before trying again.',
+                $_httpContext
+            );
+        }
+
+        if ($response->code == 401) {
+            throw new APIException(
+                'Your credentials are invalid. Please use your Bandwidth dashboard credentials to authenticate to ' .
+                'the API.',
+                $_httpContext
+            );
+        }
+
+        if ($response->code == 403) {
+            throw new Exceptions\ApiErrorException('User unauthorized to perform this action.', $_httpContext);
+        }
+
+        if ($response->code == 404) {
+            throw new Exceptions\ApiErrorException(
+                'The resource specified cannot be found or does not belong to you.',
+                $_httpContext
+            );
+        }
+
+        if ($response->code == 415) {
+            throw new Exceptions\ApiErrorException(
+                'We don\'t support that media type for this endpoint. If a request body is required, please send it to us as ' .
+                '`application/xml`.',
+                $_httpContext
+            );
+        }
+
+        if ($response->code == 429) {
+            throw new Exceptions\ApiErrorException(
+                'You\'re sending requests to this endpoint too frequently. Please slow your request rate down and ' .
+                'try again.',
+                $_httpContext
+            );
+        }
+
+        if ($response->code == 500) {
+            throw new Exceptions\ApiErrorException('Something unexpected happened. Please try again.', $_httpContext);
+        }
+
+        //handle errors defined at the API level
+        $this->validateResponse($_httpResponse, $_httpContext);
+        return new ApiResponse($response->code, $response->headers, null);
+    }
+
     /**
      * Interrupts and replaces an active call's BXML document.
      *
diff --git a/tests/BxmlTest.php b/tests/BxmlTest.php
index a97c41e..109cbc3 100644
--- a/tests/BxmlTest.php
+++ b/tests/BxmlTest.php
@@ -12,6 +12,21 @@
 
 final class BxmlTest extends TestCase
 {
+    public function testBxml() {
+        $speakSentence = new BandwidthLib\Voice\Bxml\SpeakSentence("Test");
+        $pause = new BandwidthLib\Voice\Bxml\Pause();
+        $pause->duration("3");
+        $speakSentence->voice("susan");
+        $speakSentence->locale("en_US");
+        $speakSentence->gender("female");
+        $bxml = new BandwidthLib\Voice\Bxml\Bxml();
+        $bxml->addVerb($speakSentence, $pause);
+        $bxml->addVerb($pause);
+        $expectedXml = '<?xml version="1.0" encoding="UTF-8"?><Bxml><SpeakSentence locale="en_US" gender="female" voice="susan">Test</SpeakSentence><Pause duration="3"/></Bxml>';
+        $responseXml = $bxml->toBxml();
+        $this->assertEquals($expectedXml, $responseXml);
+    }
+
     public function testForward() {
         $forward = new BandwidthLib\Voice\Bxml\Forward();
         $forward->to("+18888888888");