There are three screws on the interior skin, one on the interior lever and one or two on the face of the door near the place the latch bolt comes through. Also, you will need to unscrew and remove the inside locking pin which slides up and down to lock the door from the inside.
Once you have all of those items removed, you can gently pry the latch system out from the outside. You may have to fiddle around a bit with the shaft which comes through the inner door skin as the hole it goes through is often not quite large enough to remove the latch mechanism easily, but it did go in that way, and will come out that way.
The latch may be sealed to the exterior door skin. Use a putty knife to break that seal all the way around.
As you may know, parts for that lock are expensive and somewhat difficult to obtain, so go slow and be careful with it.