Buick Regal Owner's Manual page 57

Rear Seat Pull the head restraint up to raise it.
To lower the head restraint, press
the release button, located on the
head restraint post on the top of the
seatback, while you push the head
restraint down.
Push down on the head restraint
after the button is released to make
sure that it is locked in place.
Seats and Restraints
If you are installing a child restraint
in the rear seat, see "Securing a
Child Restraint Designed for the
LATCH System" under Lower
Anchors and Tethers for Children
(LATCH System) on page 3 42.
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