Authorize a new computer to use RW

I just bought a new MacBook Pro and cannot register RW 7.

I use RW on two machines and now cannot register the new machine.

How do I remove the old MacBook Pro and add the new one to be able to use RW 7 on the new laptop?

If you go to RapidWeaver in the menu bar, then go down to Registration, there is a deactivate button.