To move a license, you need to deactivate the license key for the old server so you can activate it on the new server. A license key can be used on only one server at a time.
If the WFE servers in your SharePoint farm have access to the Internet, see How to move your Bamboo Product License to a new server.
If your WFE servers do not have Internet access, you will need to deactivate the license key via My Bamboo. See How to deactivate your Bamboo Product License is your server doesn’t have access to the Internet.