To answer your latest question, I think that's fine since you're correcting an error. Another example of a mid-game change I think might be okay, I once forgot to include a correct letter until a few guesses later, and made sure to correct that mistake as soon as I realized it. What would not be okay would be changing the solution after the first guess has been made (unless if you somehow completely forgot what the solution is supposed to be, in which case the best thing to do would be to just start over with a new one). Alright, back to the game...
Y?