How to stop server handler

[jkikani]

-I creates server hanler to listen message on UDP Port. handle API is called first time when meaasge is recieved.
-Run same script second time, Handle API is not called. Incoming messages can be tracked via Wiershark. But It is not detected by handler.

• If same script is run with one byte data chage, It works fine.
  -Is there any way to stop server handler and start again to receive same message??????