Yes there is you can use a normal Message box and a IF then statement to look at the respond IF yes then do one else do the other. That keeps it simple.
Beware IF you do not compose it all correctly it can cause KAOS with mach4. I learned that the hard way with SheetCam. One wrong piece of code (1 line) brought down the entire program.
Beware untill we get proper documentation on the structuring of LUA in Mach4.
Just a thought, (;-) TP