I have a 99 mercury sable and want to remove the headrests from the stock front seats. Can anyone tell me how

hi. . they have clips on the side where you adjust them keep it pressed in and out they pop.
One point to be aware of.. If you remove them and and or replace with head rests made for other seats or not you can invalidate you insurance. Your insurance company not pay out if the headrests are removed and you suffer from head or neck injury...

There is a plastic retainer on one of the post move it out to UN lock and pull up hard that will do it, hope this helps.