If you need to transfer the license back and forth between two computers (i.e. PC and Laptop, or Work and Home), you can manually release the license.
Launch your active copy of Alibre, click the Utilities tab and then click Release License.
On v2017.1.2 or older:
Launch your active copy of Alibre, and on the Home window click Tools>Release License.
Then, you can activate the software with your key on your second computer and vice versa.
Note: It is ideal to save the key in a Notepad file on your computer(s), so you will have easy access to copy and paste the key to activate the software.