To see what missions need a do-over, go to app navigation bar (bottom of screen) and press the “account” icon (the one on the far right).  You will see a listing of all missions your team has performed.  Look for red bubbles; those are missions that need some attention.  You should also see a hint as to how to fix the problem.  To make corrections, select the mission you would like to revise, press the 3 dots (…) to the right of your team’s name, and tap “Edit Answer.”  It’s as easy as that!