need help door wont unlock

[turbo1969camaro]

well i have a 69 camaro that the passenger door has got locked and wont unlock i looked at it ever which away and the thing wont open it acts as if something is broken inside the door latch assembly i was wondering if anybody has heard of this or knows of a way to manual make the latch open from inside the door if i could just get it to open i will replace the latch assembly thanks any help as appreciated i have spent many hours scraching my head over this