Auto body repair & detailing: Door Panel Removal, slim jim, pushbutton

Question
I have a 1988 Olds Regency 98 on which the passenger door will not open.  The automatic/manual door lock works, but the pushbutton on the outside door handle and the lever handle inside won't activate the door release to allow the door to open.  With the door closed, I can't seem to be able to remove the door panel so I can open the door and repair the problem.   I was thinking about using a "slim jim" but I thought  that was mostly for unlocking a car door.  Any ideas.

Answer
Hello Fio,
  Have someone get inside and pull handle and push out on the door while having someone on the outside pushing the button and pulling out on the door, both at the same time.
Be sure the door is unlocked.
It sound like the latch is stuck on the striker.  Once you get it open, lubricate the latch.
Thank you,
Mike and Lisa