it is kinda a pain in the butt.the best way i have found is to roll up the upholstery and then you can see where the headrest latches and release it from inside the seatback.
Remove the head restraint by pulling the head restraint post up and out of the guide sleeve and mounting bracket.
If the mounting bracket spring clip will not disengage from the release on the head restraint post, insert a 305mm (12inch) length of thin flat stock in to the sleeve at the front side of the post . Push the spring clip out of the detent while withdrawing the head restraint.
Remove the head restraint. Remove the guide sleeve by pulling the sleeve out of the mounting bracket. Occasionally, it may be necessary to trip the locking tab on the guide sleeve to remove it form the bracket. Insert a short piece of wire with a hooked end into the sleeve. Hook onto the locking tab and pull it in. On vehicles with front seat back rear trim panel, remove the head restraint be removing the trim panel and inserting a screwdriver through the access hole in the seat back frame to release spring clip. Pull out head restraint.
Installation
Install the head restraint by inserting the post into the sleeve in the seat back. Adjust by applying hand pressure, either up or down, to the center of the head restraint assembly. The head restraint must operate smoothly throughout its range or travel and must remain in any fixed position.