How do I get my backseat back up?

I have a Chrysler PT Cruiser and I put the seats down in the back to load some stuff up. When I went to put the seats back up the lager one with the middle seatbelt would not go back up. After some investigating it looks like the seatbelt is locked (like when you hit the brakes and it locks to keep you in your seat) I am wondering how I can unlock it so that I can put my seat back up...?