As per the recently released info on it:
To begin the process, inspect the placard located at the entrance of the destination plot and select Purchase Land. A prompt for relocation will appear, allowing you to move your estate immediately after the purchase is complete. You are not required to relinquish ownership of your old plot prior to relocation. In the case of company estates and estate sharing, all players with access to the estate will receive a notification when the process is complete.