Index: firmware/App/Modes/ModeGenDialysate.c
===================================================================
diff -u -r724b64673b719eaac10b0c9dd839ad9675274911 -r6e36d2fd90b130f540494f4128951d81e7dc5ed5
--- firmware/App/Modes/ModeGenDialysate.c	(.../ModeGenDialysate.c)	(revision 724b64673b719eaac10b0c9dd839ad9675274911)
+++ firmware/App/Modes/ModeGenDialysate.c	(.../ModeGenDialysate.c)	(revision 6e36d2fd90b130f540494f4128951d81e7dc5ed5)
@@ -411,6 +411,26 @@
 
 /*********************************************************************//**
  * @brief
+ * The requestDDGenDialyasteStop function handles an TD request to stop
+ * generation dialysis mode.
+ * @details \b Inputs: Generation dialysate mode / state
+ * @details \b Outputs: mode transition
+ * @return TRUE if request accepted, FALSE if not.
+ *************************************************************************/
+BOOL requestDDGenDialyasteStop( void )
+{
+    BOOL status = TRUE;
+
+    //TODO: Transition to post gen dialysate and standby
+
+    // Transition to mode standby
+    requestNewOperationMode( DD_MODE_STAN );
+
+    return status;
+}
+
+/*********************************************************************//**
+ * @brief
  * The handleGenDDialysateDeliveryPauseState function pause the dialysate
  * delivery due to alarms conditions or some control asked to be in
  * paused state.
Index: firmware/App/Modes/ModeGenDialysate.h
===================================================================
diff -u -r5e92cbb2c29854fb60a91dc4abafeb9b08d3272c -r6e36d2fd90b130f540494f4128951d81e7dc5ed5
--- firmware/App/Modes/ModeGenDialysate.h	(.../ModeGenDialysate.h)	(revision 5e92cbb2c29854fb60a91dc4abafeb9b08d3272c)
+++ firmware/App/Modes/ModeGenDialysate.h	(.../ModeGenDialysate.h)	(revision 6e36d2fd90b130f540494f4128951d81e7dc5ed5)
@@ -56,6 +56,7 @@
 U32 getDialGoodToDeliverStatus( void );                     // Get the dialysate good to deliver status
 void setTreatmentParamUpdate( void );                       // To indicate one or more treatment parameters updated
 void updateTreatmentSettings( void );                       // Process the recent treatment parameters changes
+BOOL requestDDGenDialyasteStop( void );                     // Stop generate dialysate
 
 BOOL testDDGenDialysateDataPublishIntervalOverride( MESSAGE_T *message );   // GenD Mode data publish interval override
 BOOL testDialDeliveryInProgressOverride( MESSAGE_T *message );              // To override the dialysate delivery in progress flag
Index: firmware/App/Modes/ModePostGenDialysate.c
===================================================================
diff -u -r724b64673b719eaac10b0c9dd839ad9675274911 -r6e36d2fd90b130f540494f4128951d81e7dc5ed5
--- firmware/App/Modes/ModePostGenDialysate.c	(.../ModePostGenDialysate.c)	(revision 724b64673b719eaac10b0c9dd839ad9675274911)
+++ firmware/App/Modes/ModePostGenDialysate.c	(.../ModePostGenDialysate.c)	(revision 6e36d2fd90b130f540494f4128951d81e7dc5ed5)
@@ -37,9 +37,9 @@
 
 // ********** private data **********
 
-static DD_POST_GEN_DAILYSATE_STATE_T postGenDialysateState;           		    ///< Currently active post gen dialysate state.
-static U32 postGenDialysatePublishTimerCounter;                             	///< PostGen Dialysate data broadcast timer counter used to schedule when to transmit data.
-static OVERRIDE_U32_T postGenDialysateModePublishInterval;                      ///< Interval (in task intervals) at which to publish post-gen dialysate mode data to CAN bus.
+static DD_POST_GEN_DAILYSATE_STATE_T postGenDialysateState;                         ///< Currently active post gen dialysate state.
+static U32 postGenDialysatePublishTimerCounter;                                     ///< PostGen Dialysate data broadcast timer counter used to schedule when to transmit data.
+static OVERRIDE_U32_T postGenDialysateModePublishInterval;                          ///< Interval (in task intervals) at which to publish post-gen dialysate mode data to CAN bus.
 
 // ********** private function prototypes **********
 
Index: firmware/App/Modes/ModePreGenDialysate.c
===================================================================
diff -u -r724b64673b719eaac10b0c9dd839ad9675274911 -r6e36d2fd90b130f540494f4128951d81e7dc5ed5
--- firmware/App/Modes/ModePreGenDialysate.c	(.../ModePreGenDialysate.c)	(revision 724b64673b719eaac10b0c9dd839ad9675274911)
+++ firmware/App/Modes/ModePreGenDialysate.c	(.../ModePreGenDialysate.c)	(revision 6e36d2fd90b130f540494f4128951d81e7dc5ed5)
@@ -38,9 +38,9 @@
 
 // ********** private data **********
 
-static DD_PRE_GEN_DAILYSATE_STATE_T preGenDialysateState;           		///< Currently active pre-gen dialysate state.
+static DD_PRE_GEN_DAILYSATE_STATE_T preGenDialysateState;                   ///< Currently active pre-gen dialysate state.
 static OVERRIDE_U32_T pendingStartDDGenDialRequest;                         ///< Flag indicating TD has requested DD start the generation dialysate request(Overridable).
-static U32 preGenDialysatePublishTimerCounter;                             	///< Pre-Gen Dialysate data broadcast timer counter used to schedule when to transmit data.
+static U32 preGenDialysatePublishTimerCounter;                              ///< Pre-Gen Dialysate data broadcast timer counter used to schedule when to transmit data.
 static OVERRIDE_U32_T preGenDialysateModePublishInterval;                   ///< Interval (in task intervals) at which to publish pre-gen dialysate mode data to CAN bus.
 
 // ********** private function prototypes **********
@@ -163,6 +163,32 @@
 
 /*********************************************************************//**
  * @brief
+ * The requestDDPreGenStop function handles an TD request to stop
+ * pre-generation dialysis mode.
+ * @details \b Inputs: Pre generation dialysate mode / state
+ * @details \b Outputs: mode transition
+ * @return TRUE if request accepted, FALSE if not.
+ *************************************************************************/
+BOOL requestDDPreGenStop( void )
+{
+    BOOL status = FALSE;
+
+    //TODO: Transition to post gen dialysate if concentrate priming has been started
+
+    //TODO: Tranistion to standby if concentrate priming is not yet started
+    if ( DD_MODE_PREG == getCurrentOperationMode() )
+    {
+        // Transition to mode standby
+        requestNewOperationMode( DD_MODE_STAN );
+
+        status = TRUE;
+    }
+
+    return status;
+}
+
+/*********************************************************************//**
+ * @brief
  * The handlePreGenDialysateFillCompleteCheckState function checks the
  * hydrochamber fill and transition to next state.
  * @details \b Inputs: state
Index: firmware/App/Modes/ModePreGenDialysate.h
===================================================================
diff -u -r724b64673b719eaac10b0c9dd839ad9675274911 -r6e36d2fd90b130f540494f4128951d81e7dc5ed5
--- firmware/App/Modes/ModePreGenDialysate.h	(.../ModePreGenDialysate.h)	(revision 724b64673b719eaac10b0c9dd839ad9675274911)
+++ firmware/App/Modes/ModePreGenDialysate.h	(.../ModePreGenDialysate.h)	(revision 6e36d2fd90b130f540494f4128951d81e7dc5ed5)
@@ -44,6 +44,7 @@
 U32 execPreGenDialysateMode( void );                                            // execute the pre-gen dilaysate mode state machine (call from OperationModes)
 DD_PRE_GEN_DAILYSATE_STATE_T getCurrentPreGenDialysateState( void );            // get the current state of the pre-gen dialysate mode.
 BOOL requestDDGenDialStart( void );                                             // start generate dialysate delivery
+BOOL requestDDPreGenStop( void );                                               // stop pregenerate dialysate delivery
 
 BOOL testDDPreGenDialysateDataPublishIntervalOverride( MESSAGE_T *message );    // pre-gen dialysate publish override request
 BOOL testDDstartGenDialysateOverride( MESSAGE_T *message );                     // start gen dialysate override request
Index: firmware/App/Services/TDInterface.c
===================================================================
diff -u -r724b64673b719eaac10b0c9dd839ad9675274911 -r6e36d2fd90b130f540494f4128951d81e7dc5ed5
--- firmware/App/Services/TDInterface.c	(.../TDInterface.c)	(revision 724b64673b719eaac10b0c9dd839ad9675274911)
+++ firmware/App/Services/TDInterface.c	(.../TDInterface.c)	(revision 6e36d2fd90b130f540494f4128951d81e7dc5ed5)
@@ -350,13 +350,11 @@
         }
         else if ( DD_MODE_PREG == ddMode )
         {
-            //TODO : handle transition to post treatment after states defined.
             if ( FALSE == startPreGenRequest.start )
             {
-                // stop dialysate generation by transitioning to standby mode
-                requestNewOperationMode( DD_MODE_STAN );
+                // stop pre generate diaysate delivery
+                result = requestDDPreGenStop();
             }
-            result = TRUE;
         }
     }
 
@@ -406,9 +404,8 @@
         {
             if ( FALSE == startTxRequest.start )
             {
-                //TODO: Transition to post treatment and then standby.
-                // stop dialysate generation by transitioning to standby mode
-                requestNewOperationMode( DD_MODE_STAN );
+                // stop dialysate generation
+                result = requestDDGenDialyasteStop();
             }
             else
             {
@@ -423,9 +420,9 @@
 
                 // Signal to update treatement parameters
                 setTreatmentParamUpdate();
-            }
 
-            result = TRUE;
+                result = TRUE;
+            }
         }
     }