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.
Unsnap the plastic cover in order to expose the coat hook (1) screw.
Fig 1: Identifying Coat Hook Components
Courtesy of GENERAL MOTORS CORP.
Remove the coat hook screw.
Remove the coat hook and bezel (2) from the headliner.