I really loved this, the mechanics were great, I really liked how you used something as simple as writing a letter to a loved one.
I loved the subtlety of why this phrase needed to be rewritten and choosing was fulfilling. You really got into the minds of the characters and their motives.
I couldn't wait to write each new letter and find out what happens next. You made it thrilling even though all we did was revise.
I would love to see more stories in this form! Bravo!