NISSAN 2012 Armada - Owner's Manual - Manual (Page 29)

Adjustment
Adjust the head restraint so the center is level
with the center of the seat occupant’s ears.
To raise the head restraint, pull it up. To lower, push and hold the lock knob and push
the head restraint down.
WRS0134 LRS0888 LRS0889
1-10 Safety—Seats, seat belts and supplemental restraint system