WARNING: This page is about a different car, the 2007 Pontiac G5 Pursuit, 2007 Pontiac G5, and 2007 Chevrolet Cobalt. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: View Of Shift Control Knob & Boot
Courtesy of GENERAL MOTORS CORP.
Twist the shift control boot collar 1/4 turn and disconnect from the shift control boot (2).
Remove the shift control knob (1) upward from the shift control assembly.