Hi Amber Aggarwal,
Thanks for your interest in Syncfusion products.
Currently we have support for specifying the AppointmentID only in integer type. So, we can't specify the AppointmentID as GUID type in the current version. Hence, this issue has been confirmed as a defect. So please create a DT incident for this query so that we can update you with the patch once the issue is fixed.
You can create the DT incident from the following link.
http://www.syncfusion.com/account/dashboardIn the interests of maintaining confidentiality, we have a policy of not sharing patches or otherwise proprietary customer specific information in the public Forum.
Please let us know if you have any queries.
Regards,
Krishnaraj D