If it's the slide plate with two "ears" or tabs then the only thing you might do is to have a machine shop make up a new one... or maybe more than one if you have an entrepenurial bent. This plate is the weak link as many have found out.
How many have had the door locked and then forgot and pulled on the handle to open it? That's how I broke mine.
I just happen to have four more of these beauties on the rear doors of the funeral coach and changed out one on the drivers side and now have to open it from inside....
If this is your fix and you have someone fabricate one for you I'd buy a second ....or even a third. Just let me know.
1984 28' Funeral Coach
Former Rolling Showroom & PuttLab (now party bus)
"I'm not an expert. But I did sleep in an Airstream last night."