WARNING: This page is about a different car, the 2002 Oldsmobile Bravada, 2002 GMC Envoy XL, 2002 GMC Envoy, and 2002 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
Open the liftgate.
Fig 1: Removing Bolts Retaining Bumper Assembly To Body
Courtesy of GENERAL MOTORS CORP.
Remove the bolts that retain the bumper assembly to the body.