Revoke the Marketing Center's Access to YouTube Account

To revoke permission/unlink your Marketing Center account from your YouTube account:

1. Click on your name in the upper-right of any page in the Marketing Center.
   
   
2. Click on  App Authorization in the resulting menu:
   
   
   
   
3. Click the Revoke Access link on the row for YouTube:
   
   
   
   

At the top of the page you see a green message box with the phrase "Success! Access to youtube revoked", and the "Authorize" button will be visible again: