I put "You can change." However, after researching I realized that "Può" is 3rd person but Duo accepted my answer.
I'm going to report it just in case, but is my answer right in any context?
Your answer can be correct. "Può" goes with (capitalized) "Lei," which is the formal way of saying "you" singular. So if you were talking to an adult that you didn't know, you would say it that way.
Thanks, I just figured the formal not that long ago. But thanks for still replying, it will help someone else :)
I'm finding it hard without the hints to work out why certain words are being used.
Puo isn't in the word list.