Hi Jenne,
If I am correct, you are planning to bring up a new vSZ and move all the AP's to that vSZ.
Step 1 : Bring up the new vSZ with new Ip address
Step 2 : Move the cluster configuration from old vSZ to new vSZ
Step 3 : Run a script on existing vSZ, so that all the Ap's are aware of the new vSZ Ip address
Step 4 : Shutdown the existing vSZ, so that ap's can join the new vSZ
Please make sure you take a downtime for this complete process.
For assistance with License and the Script, I would request you to please open a case with Support.
Regards,
Arun N