Friend Problems and What I should Do and What you Would Do??

Sooo it's the middle of the week and there's this show called Modern Family and it's pretty funny. I have this friend and she is mad at her other friend and they are both best friends.... so and they are fighting because we had to look over someone else's work and the other friend said that she did something wrong but the friend knows that she didn't do anything wrong so she says no I din't do anything wrong but then the other friend says oh stop being so bratty and she says I'm not bratty! And so she is mad at her and I was wondering what would you do if you were in this kind of situation.......