A managed SEP client will not change group or domain membership in SEPM after some operations, such as importing new communications settings (SyLink.xml) or re-installing or upgrading the client with a new package exported from the SEPM.
To otherwise change the group or domain membership of an existing managed SEP client, use one of the following methods:
- Use the move operation in the SEPM clients list (only available for changing groups, not domains). Simplest.
- Delete the client's entry in the SEPM clients list, then deploy new communication settings to client *
- Delete Hardware ID files from client, then deploy new communications settings to client **
- Use the MoveClient tool in the /Tools/NoSupport directory of the SEP product media.
I would recommend to go through this article for more details:
A managed Symantec Endpoint Protection client will not change group or domain membership after some operations
http://www.symantec.com/docs/TECH230267
or else need to follow this article
How do I move a large number of SEP clients to a new group at once?
http://www.symantec.com/docs/TECH98302