I heard Jeff Daniels on a podcast talking about how you do not change one word of Sorkin's dialogue (I guess when he's the director as well as the writer) because he doesn't allow it. He said, and I'm paraphrasing, the only time Sorkin allows an actor to do that is basically once they've been working with him so long their changes are basically the way Sorkin writes anyway.

Of course, Jack is Jack, so . . . what are you gonna do?