Sometimes it is necessary to edit the match scores after a winner has been reported. Once scores have been reported, the match identifier (letter on the left side of the match) will become a menu allowing you to either edit or reopen the match.
Actions taken from this menu will impact dependent matches (if there are any). For example, if match A is edited so that player 8 wins instead of 1, match E will require a new score.
Similarly, reopening match A clears scores for matches E and G.