The rear outboard head restraints can be removed if they interfere with the proper installation of the child restraint.
To remove the head restraint:

Warning
With head restraints that are not installed and adjusted properly, there is a greater chance that occupants will suffer a neck/ spinal injury in a crash. Do not drive until the head restraints for all occupants are installed and adjusted properly.
To reinstall the head restraint:

If necessary, press the height adjustment release button to further lower the head restraint.
See Head Restraints on page 3-2.
Securing a Child Restraint Designed for the LATCH System
Replacing LATCH System Parts After a CrashSafety System Check
Now and then, check that the safety belt reminder light, safety belts, buckles,
latch plates, retractors, and anchorages are all working properly.
Look for any other loose or damaged safety belt system parts that might keep
a safety belt system from doing its job. See your dealer to have it rep ...
OnStar Additional Information
Transferring Service
Press to request account transfer
eligibility information. The Advisor can assist in canceling or removing account
information.
Selling/Transferring the Vehicle
Call 1-888-4-ONSTAR immediately to terminate your OnStar services if the vehicle
is disposed of, sold, trans ...
Ignition Positions
The ignition switch has four different positions.
The uplevel key must be fully extended to start the vehicle.
To shift out of P (Park), the ignition must be in ON/RUN and the regular brake
pedal applied.
1 (STOPPING THE ENGINE/LOCK/ OFF): When the vehicle is stopped, turn the ignition
sw ...