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.
Open the liftgate.
Remove the bolt that retains the child restraint tether anchor to the floor panel.
Remove the child restraint tether anchor from the floor panel.