Move school license from a pc machine to server machine

How can we move a license to a server machine when it is a school license.

The school has a school license and at the beginning the server machine was not working, so they installed the license on a computer were was used like a server machine. Now, the school has the server machine working and I would like to know, how can we move this license (pc macadress) to another macadress (to server machine).