Is it illegal to change the dates written on a doctor's note? There was no signature forgery, just changed the dates on a doctor's note from 6/29/09 to 6/30/09-7/2/09. Is this illegal? What kind of trouble can someone get in for doing this if they're caught? I'm not sure if this was the right forum category to place this in, but I'm hoping someone can help me out. Thank you!