If you have reinstalled your system and forgot to log out of your Spine license, you can reset your license. This will require all users who used the original activation code to reactivate when they restart Spine. To proceed with the reset, please contact Esoteric Software from the email address registered with your license. You can email them at [contact@esotericsoftware.com](mailto:contact@esotericsoftware.com).

For more information, you can also visit the Spine license recovery page to retrieve your license details if needed.

In addition to what Spinebot said, if you're not an ENT user you may simply use your license on the new pc: Even if you don't log out, old installations that are no longer used are automatically discarded by the licensing system.
https://esotericsoftware.com/support#Can-I-install-Spine-on-a-new-computer