diff --git a/src/Hyperwallet/Model/BankAccount.php b/src/Hyperwallet/Model/BankAccount.php
index 5ace32fa..5cf081bb 100644
--- a/src/Hyperwallet/Model/BankAccount.php
+++ b/src/Hyperwallet/Model/BankAccount.php
@@ -1,6 +1,8 @@
 <?php
 namespace Hyperwallet\Model;
 
+use Hyperwallet\Util\StringToDataConverter;
+
 /**
  * Represents a V3 Bank Account
  *
@@ -784,11 +786,12 @@ public function getDateOfBirth() {
     /**
      * Set the date of birth
      *
-     * @param \DateTime|null $dateOfBirth
+     * @param string $dateOfBirth |null
      * @return BankAccount
      */
-    public function setDateOfBirth(\DateTime $dateOfBirth = null) {
-        $this->dateOfBirth = $dateOfBirth == null ? null : $dateOfBirth->format('Y-m-d');
+    public function setDateOfBirth($dateOfBirth = null)
+    {
+        $this->dateOfBirth = StringToDataConverter::convertStringToDate($dateOfBirth, 'Y-m-d');
         return $this;
     }
 
diff --git a/src/Hyperwallet/Model/BankCard.php b/src/Hyperwallet/Model/BankCard.php
index 143023be..d58952bf 100644
--- a/src/Hyperwallet/Model/BankCard.php
+++ b/src/Hyperwallet/Model/BankCard.php
@@ -1,6 +1,8 @@
 <?php
 namespace Hyperwallet\Model;
 
+use Hyperwallet\Util\StringToDataConverter;
+
 /**
  * Represents a V3 Bank Card
  *
@@ -225,11 +227,12 @@ public function getDateOfExpiry() {
     /**
      * Set the bank card expiry date
      *
-     * @param \DateTime $dateOfExpiry
+     * @param string $dateOfExpiry |null
      * @return BankCard
      */
-    public function setDateOfExpiry(\DateTime $dateOfExpiry = null) {
-        $this->dateOfExpiry = $dateOfExpiry == null ? null : $dateOfExpiry->format('Y-m-d');
+    public function setDateOfExpiry($dateOfExpiry = null)
+    {
+        $this->dateOfExpiry = StringToDataConverter::convertStringToDate($dateOfExpiry, 'Y-m-d');
         return $this;
     }
 
diff --git a/src/Hyperwallet/Model/Payment.php b/src/Hyperwallet/Model/Payment.php
index 7662de4a..e9e699bb 100644
--- a/src/Hyperwallet/Model/Payment.php
+++ b/src/Hyperwallet/Model/Payment.php
@@ -1,6 +1,8 @@
 <?php
 namespace Hyperwallet\Model;
 
+use Hyperwallet\Util\StringToDataConverter;
+
 /**
  * Represents a V3 Payment
  *
@@ -201,11 +203,12 @@ public function getReleaseOn() {
     /**
      * Set the payment release date
      *
-     * @param \DateTime $releaseOn
+     * @param string $releaseOn |null
      * @return Payment
      */
-    public function setReleaseOn(\DateTime $releaseOn = null) {
-        $this->releaseOn = $releaseOn == null ? null : $releaseOn->format('Y-m-d\TH:i:s');
+    public function setReleaseOn($releaseOn = null)
+    {
+        $this->releaseOn = StringToDataConverter::convertStringToDate($releaseOn, 'Y-m-d\TH:i:s');
         return $this;
     }
 
@@ -240,7 +243,7 @@ public function getProgramToken() {
 
     /**
      * Set the payment program token
-     * 
+     *
      * @param string $programToken
      * @return Payment
      */
diff --git a/src/Hyperwallet/Model/TransferMethod.php b/src/Hyperwallet/Model/TransferMethod.php
index b7ce38d2..ac5cc5c0 100644
--- a/src/Hyperwallet/Model/TransferMethod.php
+++ b/src/Hyperwallet/Model/TransferMethod.php
@@ -1,6 +1,8 @@
 <?php
 namespace Hyperwallet\Model;
 
+use Hyperwallet\Util\StringToDataConverter;
+
 /**
  * Represents a V3 Transfer Method
  *
@@ -191,7 +193,7 @@ public function getCardBrand() {
     public function getDateOfExpiry() {
         return $this->dateOfExpiry ? new \DateTime($this->dateOfExpiry) : null;
     }
-    
+
     /**
      * Get the bank account id
      *
@@ -861,11 +863,12 @@ public function getDateOfBirth() {
     /**
      * Set the date of birth
      *
-     * @param \DateTime|null $dateOfBirth
+     * @param string $dateOfBirth |null
      * @return TransferMethod
      */
-    public function setDateOfBirth(\DateTime $dateOfBirth = null) {
-        $this->dateOfBirth = $dateOfBirth == null ? null : $dateOfBirth->format('Y-m-d');
+    public function setDateOfBirth($dateOfBirth = null)
+    {
+        $this->dateOfBirth = StringToDataConverter::convertStringToDate($dateOfBirth, 'Y-m-d');
         return $this;
     }
 
diff --git a/src/Hyperwallet/Model/User.php b/src/Hyperwallet/Model/User.php
index 1e5a2094..d4645727 100644
--- a/src/Hyperwallet/Model/User.php
+++ b/src/Hyperwallet/Model/User.php
@@ -1,6 +1,8 @@
 <?php
 namespace Hyperwallet\Model;
 
+use Hyperwallet\Util\StringToDataConverter;
+
 /**
  * Represents a V3 User
  *
@@ -362,11 +364,12 @@ public function getDateOfBirth() {
     /**
      * Set the date of birth
      *
-     * @param \DateTime|null $dateOfBirth
+     * @param string $dateOfBirth |null
      * @return User
      */
-    public function setDateOfBirth(\DateTime $dateOfBirth = null) {
-        $this->dateOfBirth = $dateOfBirth == null ? null : $dateOfBirth->format('Y-m-d');
+    public function setDateOfBirth($dateOfBirth = null)
+    {
+        $this->dateOfBirth = StringToDataConverter::convertStringToDate($dateOfBirth, 'Y-m-d');
         return $this;
     }
 
diff --git a/src/Hyperwallet/Util/StringToDataConverter.php b/src/Hyperwallet/Util/StringToDataConverter.php
new file mode 100644
index 00000000..d98168b9
--- /dev/null
+++ b/src/Hyperwallet/Util/StringToDataConverter.php
@@ -0,0 +1,14 @@
+<?php
+
+
+namespace Hyperwallet\Util;
+
+
+class StringToDataConverter
+{
+    static function convertStringToDate($string, $format)
+    {
+        $stringToDate = $string === null ? null : new \DateTime($string);
+        return $stringToDate == null ? null : $stringToDate->format($format);
+    }
+}
\ No newline at end of file
diff --git a/tests/Hyperwallet/Tests/Model/ModelTestCase.php b/tests/Hyperwallet/Tests/Model/ModelTestCase.php
index a6ec84ca..301c209c 100644
--- a/tests/Hyperwallet/Tests/Model/ModelTestCase.php
+++ b/tests/Hyperwallet/Tests/Model/ModelTestCase.php
@@ -130,7 +130,7 @@ protected function performGetterAndSetterReturnValueIsSetIfValueIsProvidedAndDef
         $setter = $this->clazz->getMethod($setterName);
 
         $this->assertEquals($valType, $getter->invoke($instance));
-        $this->assertEquals($instance, $setter->invoke($instance, $newValParam));
+        $this->assertEquals($instance, $setter->invoke($instance, $newVal));
         $this->assertEquals($newValParam, $getter->invoke($instance));
 
         $data2 = array();
@@ -173,7 +173,7 @@ protected function performGetterAndSetterReturnValueIsSetIfValueIsProvidedAndDef
         $setter = $this->clazz->getMethod($setterName);
 
         $this->assertNull($getter->invoke($instance));
-        $this->assertEquals($instance, $setter->invoke($instance, $newValParam));
+        $this->assertEquals($instance, $setter->invoke($instance, $newVal));
         $this->assertEquals($newValParam, $getter->invoke($instance));
 
         $data2 = array();
diff --git a/tests/Hyperwallet/Tests/Util/StringToDateConverterTest.php b/tests/Hyperwallet/Tests/Util/StringToDateConverterTest.php
new file mode 100644
index 00000000..def6a707
--- /dev/null
+++ b/tests/Hyperwallet/Tests/Util/StringToDateConverterTest.php
@@ -0,0 +1,33 @@
+<?php
+
+
+namespace Hyperwallet\Tests\Util;
+
+
+use Hyperwallet\Util\StringToDataConverter;
+
+class StringToDateConverterTest extends \PHPUnit_Framework_TestCase
+{
+
+    public function testShouldConvertStringToDateIfAcceptedParameterIsNotNull()
+    {
+        $format = 'Y-m-d';
+        $stringToConvert = '2019-12-31';
+
+        $convertedDate = StringToDataConverter::convertStringToDate($stringToConvert, $format);
+        $originalDate = new \DateTime($stringToConvert);
+
+        $this->assertEquals($originalDate->format($format), $convertedDate);
+    }
+
+    public function testShouldReturnNullIfAcceptedParameterIsNull()
+    {
+        $format = 'Y-m-d';
+        $stringToConvert = null;
+
+        $convertedDate = StringToDataConverter::convertStringToDate($stringToConvert, $format);
+        $originalDate = null;
+
+        $this->assertEquals(null, $convertedDate);
+    }
+}
\ No newline at end of file