1. Go to appleid.apple.com 2. Log in using your Apple ID and password. 3. Scroll down to "Devices." 4. Click on the name of the Macbook Pro. 5. A small window will open; click on "Remove." You may also want to read Apple's advice on [What to do before you sell or give away your Mac][1]. [1]: https://support.apple.com/en-us/HT201065