Hello Suryakant,
The SEP clients find the management server by looking at the Management Server List they are configured to use. By default when you install the SEP Manager it creates a default Management Server List that contains the IP address of the manager and its name. If you just change the address of the server SEPM will update this list but that will not change the server being referrence by those clients which have already been deployed.
You can create your own Management Server List and have the clients use it instead. If you were to create a new Management Server List with only the name of the management server it would force the clients to resolve the IP address of the management server from DNS or NetBIOS and all should be well as long as you change DNS when you change the IP on the server.
Prior to make any changes take necessary backups.
SEP 11.x: http://www.symantec.com/docs/TECH102333
SEP 12.1: http://www.symantec.com/docs/TECH160736
You can refer the following steps as well:
1. Change the Management Server List (MSL): Policies > Policy Components > Management Server Lists > (edit the list in use - Group and Location Use Count)
Under 'Priority 1' add the new IP address in the form: <IP_address>:<port>
Example:
- 192.168.1.1:8014
Note: If you are using the default MSL you have to create a new Management Server List and add the existing IP addresses/hostnames (as the default) and add the new IP address as well - so that you have the current and the future IP addresses. In alternative, Copy/Paste the existing MSL and give it a different name.
2. After, select Ok and Assign the new list to your client groups.
3. Select each group > right-click and select Run Command on Group > Update Content, to update the current settings in all clients (this also helps to assure that they receive the new MSL)
4. Assure that all the clients have the latest policy version
5. Then, it should be ok to change the IP address of the SEPM server
6. The procedure can be repeated to remove the old IP address from the MSL