WARNING: This page is about a different car, the 2002 Buick Regal and 2002 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.
Position the right front seat to the forward position.
Remove the nut from the seat belt buckle.
Fig 1: Identifying Right Front Seat Belt Buckle
Courtesy of GENERAL MOTORS CORP.
Remove the seat belt buckle from the right front seat.