There is a metal pin / clip under the plastic base (the part that attaches to the seat) under the plastic you will see a metal ring / clip that looks like a paper clip. Slide a screwdriver down and pull it forward, the headrest will slide out.
There is a metal pin / clip under the plastic base (the part that attaches to the seat) under the plastic you will see a metal ring / clip that looks like a paper clip. Slide a screwdriver down and pull it forward, the headrest will slide out.