not sure what you mean, you can operate a fair amount of functions while the game is playing, like bidding on players, changing your next game's line-up, hiring new staff,...
But you can't do anything about the game in progress. 15 minutes before the game starts is the time where it locks in, and you can't change a thing about it anymore. All you can do is watch and see how it goes, and learn from it for your future games.
They are not your friends; they dispise you. I am the only one you can count on. Trust me.