Just reactivate. Every license has 5 activations and you can reset old activations within your my.presonus.com account.
To reset your Studio One Activations, please do the following:
1. Log into your user account at http://my.presonus.com
2. Once logged into your account, select the icon at the top of the screen called "My Products" click that to reveal the Hardware and Software Registrations for your account.
3. Click the "Software" Tab, which will show all of your registered software.
4. Locate the copy of Studio One that you which to manage.
5. Once located, Click on the "View More Details" located directly below the copy you wish to manage.
6. Locate the registration code related to the copy you wish to manage and click on "Manage Activations" link to the right of it.
7. An expanded window will open; revealing all activations linked for that registered product key.
8. Click on the "Remove" button to remove and of the activations from the list.
9. Once completed, select "Close" at the bottom right of this window to close the window.