WARNING: This page is about a different car, the 2010 Cadillac SRX. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: View Of Radio Antenna
Courtesy of GENERAL MOTORS CORP.
Callout
Component Name
1
Radio Antenna Procedure: Rotate the mast counterclockwise in order to release the mast from the antenna base.