The Symantec Endpoint Protection Manager (SEPM) is going to be assigned a new IP address, and the managed clients which report to this SEPM need to be provided with the new IP prior to this change being made.
Failure to provide the clients with the new IP before changing it would result in the clients becoming orphaned, assuming they are not set to also use SEPM hostname for communications, or cannot resolve the SEPM hostname.
To change the IP Address that clients use to communicate with the Symantec Endpoint Protection Manager, create a Management Server List that has both the old and new IP Addresses configured, and assign that policy to all the groups.
NOTE: These steps are intended to be performed before moving the SEPM to the new IP address. Once these steps have been completed, it is recommended to wait for at least several heartbeat cycles before committing the SEPM IP change, to allow clients time to receive the new Management Server List which contains the new SEPM IP.
Once the SEPM IP change is completed, the old IP address can be removed from the new Management Server List. Any clients which fail to report to the SEPM after the IP is changed can have communications restored with a Communications Update Package pushed from the SEPM console.