Is your Prime Infrastructure running on a VM?
If so, then just vMotion it over. You'd of course require the same network port groups available to the target ESXi host.
If that's not an option (or if you have physical appliance) then you could backup the current Prime Infrastructure and then restore onto a new instance on the target system. Isolate the interfaces until you are ready to go live.
There are other options as well of increasing complexity.
