Well that's sort of the problem. The new 5.5 vCenter server is installed in evaluation mode, the old one will be shut down.
But because I cloned the new VM from the old VM, the new VM already has the license assigned that I would want to use for it.
Are you saying I need to either build a new vCenter server from scratch, or purchase another license? Surely there is a way to remove the license. Is this something that could be done by Vmware if I opened a ticket?