Hi,
Please follow the steps mentioned in this solution to change the IP address:
http://www.symantec.com/connect/forums/recommended-procedure-sepm-manager-ip-address-changeBasic steps:
1. Edit the management server list(s) and create an additional Priority 1 entry for the NEW ip address.
2. Ensure that the clients pull the new policy.
3. Use the Wizard to change the servers IP address.
4. Verify that the clients are still communicating.
5. Edit the managment server list to remove the entry with the old IP address.
And also can refer to this document:
http://service1.symantec.com/support/ent-security.nsf/854fa02b4f5013678825731a007d06af/e2ac3b646ae21969882573c20063533f?OpenDocumentRegards,
Pradeep Jhala