I can't find documentation on the best way to swing the voicemail ports from my existing Unity 4.0.4 server to a new 4.0.4 server with a new IP address in a different subnet. We're running CallManager 4.1-- (I'm using the new server to then upgrade to Unity 5.x and have already done a DiRT restore of the active database). We are migrating voicemails from Exchange to Exchange using ExMerge.
We have two CallManager servers (pub/sub) and end state will be one Unity server (the new hardware only). The old Unity is still running at present.