WARNING: This page is about a different car, the 2003 Oldsmobile Bravada, 2003 GMC Envoy XL, 2003 GMC Envoy, and 2003 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
Remove the screws from the inboard/outboard rear seat back hinge covers.
Remove the rear seat back hinge cover halves.
Fig 1: Screws From Inboard/Outboard Rear Seat Back Hinge Covers