WARNING: This page is about a different car, the 2004 Pontiac Aztek and 2004 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.
Open the liftgate.
Remove screws from liftgate striker.
Remove liftgate striker and spacer from vehicle.
Fig 1: View Of Latch Striker & Spacer (Rendezvous)