Hi,
Thank you for posting in Symantec community.
I would be glad to answer your query.
Are they two standalone servers? or they replicating with each other? sharing the same database?
If they are Standalone server then no need to stop secondary server services.
If they are replicating then need to break the replication piror to start an upgrade & Before you upgrade, you must manually stop the Symantec Endpoint Protection Manager service on every management server in your site. After you upgrade, the service starts automatically.