如何在fullcalendar上只将更新的事件作为json发送到服务器？

I have a appointment booking usecase where I get the all previously stored appointments when the user clicks. After I add new appointments or change existing ones and click submit, all appointments including the older ones should go to the server, and there by creating duplicates. What I want is to set only those appointments in the a json that were created by events. I have a appointment booking usecase where I ge