Transferring a Craft License to a New Domain
Each Craft license may only be used on a single public domain at a time (see How Craft License Enforcement Works for more info).
If you’ve purchased Craft Pro, and decide that you want to use that license on a different public domain, just move your craft/config/license.key file over to the Craft install on the new domain.
When you do that, you may see an alert at the top of the Control Panel on the new domain, indicating that the license.key file Craft is currently using is not licensed for the current domain.
If you see that, just click the “Transfer it to this domain?” link, and the license will be reassigned to the current domain.