If you are given a chance to re-do a day in your life, when was it and what will you do?

I'll go back in my senior year in high school, at the rooftop, I'll tell that person the words I wasn't able to voice out that I still carry, now that I'm in my 4th year in college. And it still hunts me every time. I'll spend the whole day making the wrongs right. Saying the right things to avoid one of my biggest regrets and mistake.