I sold my iPhone 3GS and just received an email about "my" genius bar appointment. The new owner made this appointment. Is there any way to completely untie my info from the phone? Thanks!
Erase it completely. Go to Settings > General > Reset > Erase All Content and Settings Or plug it into iTunes and click Restore, and then when it finishes rebooting do not restore from back up or set up as a new phone. Just give it to the person you sold it to.
Maybe the serial # is tied to your account. If your in contact with him tell him to change the account info on the phone when he goes to the genius bar.