If you decide to disconnect your Classmates and Facebook accounts, you can do so by going to your Account page, found under the gear icon 
the orange bar at the top right of any page. Select Privacy, then look for the Facebook Connect section and click Disconnect.
After making this change, if you'd like to remove or replace any profile content that was populated from Facebook, visit your Classmates profile under your name/photo in the orange bar at the top of any page.
Click here to go to your Account Privacy settings.