After a considerable and difficult effort I was able to remove the tv from the bracket
The top of the bracket has a tab that fits into a slot in the wall bracket.
The bottom of the bracket has two spring loaded tabs that fit into the holes in the wall mount
To free it in the future, I'll use a long bladed screw driver to lift the leaf spring on the bottom tabs and the tv will pivot out from the bottom allowing the top tab to drop out of the wall mount slot.
Just not much room to reach behind the tv to work on it.