CJ7 Windshield Wiper Problem

Hi,

76 CJ7
The people who installed my windshield put on one of my windshield wipers pointing the wrong direction.
In other words, the passenger side was pointing left (facing the vehicle) and the driver's side one was pointing right.
I didn't think too much about it because they seemed to work and it was in the middle of a blizzard and I was anxious to get out of
there.
Well before long, the driver's side one (the one that is on the wrong way) flopped below the windshield.
It appears that it is actually 90 degrees off of where it should be.
There is a nut on the front of the wiper (between the blade and the windshield).
I thought that loosening this would let me take the wiper off or something - but it doesn't seem to do any good.
Folding down the windshield, and looking at the linkage inside, there appears to be no way to change the position of the wiper
without serious difficulty.
Unfortunately I can't take the Jeep back to the people who did it because they are too far away.
How do I get this wiper back where it should be?

Thanks