Upgrading Symantec Endpoint Protection (SEP) 11 to SEP 12 on XP/Win7

Hi,

I have a client that needs to upgrade/replace its SEP clients (version 11) (running under XP and Win7) but the current management console (SEP 11) is not accessible.

A new console running SEP 12 will be installed. What is the best way to upgrade/replace the SEP clients on the workstations?

Thanks in advanced!

Jean D.