Remove a headrest that was inserted backwards, and now, I can't get it out to place it properly?

What is your question?

My knucklehead brother thought that the headrest for the front passenger's seat was installed incorrectly, so, he pulled it out, turned it around, and forced it into the holes at the top of the seat. When I discovered what he had done, I tried to pull the headrest out so as to install it correctly. I tried a little WD-40 to lube things up and make them slick. Is there a particular way that the headrest (installed / inserted backwards) can be moved / removed and corrected???