Ok say I'm playing in a standard 3-round tournament and I have one fig on my team with Avengers TA and a Thunderbolts feat slapped on him, am I required to use the same ATA the entire tournament or can I change it from battle to battle? Just curious cause if I have to pick the same one it'll change the way I want to build my team. Let me know

From the player's guide:

 Avengers characters using Thunderbolts may change their chosen team ability with each new round of a tournament.