[B_Deemer]

You have to remove the small plastic covering for the side without the lock. I did this by prying (gently) with a flat head screwdriver under the outer edge of the cover. Once the cover pops up, you will see that there is a spring loaded lock. Basically, it's the same lock as the other side but there is no button. Once you see it, it should be pretty obvious how to release the lock. Press the tab to compress the springs and the headrest will lift right out.

Hope this helps.