@mrac1 OKAY! Back to this.. Finally updated, and Calling the macro generates a popup window, but doesn't pause the print, or move the print head out of the way, etc. So, the Macro is calling, but it's not doing anything other than generating an OK button. Thoughts?
My Macro Script (Super simple):
M400 ; Wait for moves to complete
G1 X10 Y10 F3000 ; Move nozzle to the front
M291 P"Change Filament" ; Display message
G1 R1 ; go back to the last print move