Reversing a bad tune

[DVT873]

This is probably a dumb question. When a demandate program gets put in an ECM, what all happens? What needs to happen to reverse it? Is it just a matter of flashing a stock tune into it? Or is there a level of programming below the Features and Parameters we see with INSITE? A level that needs C--T--- to access and correct.

I assume there is a level below INSITE. Asking because I have a medium duty 13 letter shi#t-spreader that somebody demandated. The owner wants it put back to stock.