Thank you to all who offered assistance.

After reading a post from Dies from SA suggesting to take the try to take the
lock apart, I experimented further using the front door locks as Guinea pigs.
I could not see anyway to dismantle the latch while in the installed position
with the door closed. I did find another solution which will work for broken
front door latches as well.

The latch assembly is composed of a main latch which looks like an upside
down "U" which has a notch intended to engage a smaller latch. The upper
latch pivots down whilst the lower latch pivots upwards. First click would be
the main latch engaging the stud attached to the vehicle body. As the door is
closed inward more, the two latches interlock around the stud.

After simulating a closed latch on the open front door, I engaged the lock
button. Then I used a screwdriver to depress the lower latch. That disengaged
the mechanism from the fully locked position to the first detent. Once in
that position, I was able to operate the lock by depressing the door handle.

Now I can easily replace the defective latch assembly.

BenT
San Francisco