Index: firmware/App/Modes/ModeTreatmentParams.c
===================================================================
diff -u -r766708fceb0bdf1af8c7897df29d4f5036bfd3db -rbb114842e73659f097bb8b8ec0d670bfa4f8cb73
--- firmware/App/Modes/ModeTreatmentParams.c	(.../ModeTreatmentParams.c)	(revision 766708fceb0bdf1af8c7897df29d4f5036bfd3db)
+++ firmware/App/Modes/ModeTreatmentParams.c	(.../ModeTreatmentParams.c)	(revision bb114842e73659f097bb8b8ec0d670bfa4f8cb73)
@@ -221,14 +221,17 @@
 BOOL signalUserCancelTreatment( void )
 {
     BOOL result = FALSE;
+    REQUEST_REJECT_REASON_CODE_T rejReason = REQUEST_REJECT_REASON_NOT_ALLOWED_IN_CURRENT_MODE;
 
     if ( MODE_TPAR == getCurrentOperationMode() )
     {
         treatmentCancelled = TRUE;
         result = TRUE;
+        rejReason = REQUEST_REJECT_REASON_NONE;
     }
-    sendTreatmentStartResponseMsg( result, 0 ); // TODO - provide reason code if rejected
 
+    sendInitiateTreatmentResponseMsg( result, rejReason );
+
     return result;
 }