Outside dooor handle

remove door panel disconnect linkage remove retaining screws -replace handle

You have very few options with this one. Child lock switches are designed to be hard to get to so they can't be turned off by accident.
Your best option is to take the vehicle to a good mechanic or a good bodywork specialist and have them do it.
What do you mean by the door handle is 'Broken'? Is it loose and one one piece or is it physically broken off?
To fix this yourself your going to have to 'break' something to get to the problem. If the outside handle is broken off, you could try using a piece of wire to hook the release mechanism through the hole left by the handle. If it isn't, you could also try removing the door card inside the vehicle to access the release from inside the door. That's where you might need to damage the panel to get it off!

You don't say if it's in or outside handle, either way:

1. go around the car and open the good door
2. then you can unlock the broken door
3. use the inside handle, if gone, use outside to open door,
4. go buy a new handle and replace it

MDS

Get a replacement handle REmove door trim to get to the retaining bolts holding the old door handle in place. Replace and reassemble in reverse

your linkage rod to the outside door handle has disconnected , if you open up the door panel to access the lock linkage rods you will find the rod that is disconnected . There is a plastic bushing the rod is secured with if it is broken you must replace it , if the rod will not stay in place replace the bushing , hope this helps you out

The outside door handle may be broken or may have become disconnected from the rod that allows the door to open. Sometimes the ther is a plastic clip that connects the rod to the door handle and could be broken any parts store will have replacement clips. Whatever the problem is, the door panel will have to be removed to be able to inspect the condition of the door handle and parts attaching to it.

I have exactly the same problem with a 2002 X5. The passenger door handle has no resistance on it from either inside or outside and as such I cannot open the door. I am now wondering how to get the trim off to see what is bust inside. Anyone got any ideas??

well, not much to go with but if it opens from the inside then you have a broken clip or rod on the outside handle of the door now if it opens on the outside then vice versa,you have a broken clip or piece off of the inside handle

The repair will require removal of the door panel and adjustment/replacement of the rod that connects the outside handle to the lock mechanism, or replacement of the handle itself.

spray the latch with wd-40