how to change the default port of sep client and manager?
Look this artical hope it help you.
Symantec Endpoint Protection 11.x: How to Change the ports used for communication between the Manager and clients
whats the version of SEP you are using, if you are using 11.X above document explains it very well.
if its 12 check this document
Have a look here as well:
Check this thread may be help you.
Thanks In Advance