Thank you for allowing me to assist you, my name is Joe and I will be happy to assist you with your concern today.
This means that either the lock rods are not unlocking the latch (disconnect the rods and manually move on the latch to unlock), if that does not work this means there is an actual problem with the latch, you will need to create a way to get the latch to open which usually requires a screwdriver and forcing the latch open (from inside the door), in some cases the latch will need to be cut open to get it to release.
The best place to start is by disconnecting all rods from the latch and working the lock manually on it and the release which will eliminate the rods, locks and handles.
That's pretty much it, there's no special way to get the door open as it will require manually hands on approach to get the latch open, some can be a real bugger.
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