[the_gentlegiant]

You need to replace all M6 commands with M00, and comment out all Txx addresses.

M00 stops the program for you to manual toolchange
The Txx removal stop the carousel from rotating to pre-select a tool.

Yes all that is the easy way to do it, but this isn't the first person I've seen lately wanting something like this. Seems nobody either wants to or has the ability to modify a Post or Program manually. Even though they're asking the machine to forget about half of its functions, they still want it done without any personal intervention. Go figure. Really... the time it would take to modify programs would be almost nothing. A couple text based Find & Replaces and that's it.