There is no charge for transferring licenses between servers. In ACC 5 you can disable the license on your own via the "admin tool". ACC 4 you have to call support.
Just to clarify the fee free to upgrade. If you have a ACC 4 server with any license perchased and installed on the server after September 1st 2012 you get a free upgrade to ACC 5. The upgrade license cost is the same price a adding a single license to the server. If you have a customer that wants to upgrade to ACC 5 but they are not eligible for the free upgrade sell them a singe ACC license. At this point they get an extra license PLUS the free gateway license and free upgrade to ACC 5.
We recently installed a new server with more space and power to add capacity, but the client has a 30 day minimum video retention policy. The ACC4 server was eligible for 100% free upgrade. The current server was a Dell / Avigilon R720 rack server, and was showing its age with raid cache battery issues, and an occasional disk error on the raid6 array.
The official process for the free upgrade is to do an in-place upgrade. Explaining our concerns about this server to Avigilon Support, with remote access, they copied the licenses, converted them to unused ACC5 licenses, added a 30 day trial ACC4 license back onto this older server, for recorded video access, The converted license were put on the new server, allcameras were moved, and after 30 days, the old server gets new cache batteries, new drives, new bios, new embedded OS, placed back into service, and the cameras are moved around for best load balance.
This was all done on an early Sunday morning with Avigilon support.... Our clients have all been surprised with the low to no, and almost seamless upgrade from 4 to 5. Your experience shouldn't be anything less... Cheers.....Andy