how to open jammed rear doors?

Hi all, does anyone know how can I open jammed rear doors?
my central locking in o/s rear doors stopped working so I wanted to change it but I can't open the doors, both handles doesn't work, locking pin doesn't go up. I've fully opend the window but I can't see anything that I could pull/push to try to open the door, any ideas? Thanks

Silly question but have you tried the manual lock button on the inside of the door.
This should override the central lock if the dead lock is not on.

Give the drivers door card a onceover, it sounds like it could be the connector on the lock door/window section