If you want to reclaim one of your authorizations from a machine that you are no longer using, you can do that by logging into your account and going to Manage Devices. You will see a list of your activated devices, with a “Deactivate” button next to each one.  You do not need to have access to a machine in order to deactivate it.  So if your computer is stolen or crashes, you can still reclaim its licenses on the Manage Devices page.