Hi,
You can simply move an IAP to a new cluster with or without factory reset. always better to reset before join it to a new cluster. as soon as newly joined IAP receives Master beacon, it will change it self as a slave and pull the configuration from the VC.
One thing you need to keep in your mind is, image update. if the new IAP and existing VC are of the same hardware ( Orion, Pegasus etc..) Image sync will happen automatically but if they are different Image should be updated either through Airwave or manually.
Hope you got your answer,
Please feel free for any further query on this.