AutoCAD lisp that can convert between two different attributes

I have two different attributes I'm constantly working on within AutoCad that represent the height of a specific point; Today, I switch between them manually, but I want to easily be able to convert between the two attributes back and forth by a command.

I assume AutoCAD lisp that can convert between to different attributes is the right solution.

Attached is an AutoCAD file with the two attributes - I currently switch between them manually.