AFAIK, you cannot delete the main header, Jay. But, you can change the text to be empty. You're stuck with an empty box.
In the Format tab, you can change certain areas of the schedule to NOT have borders. But it seems we can't turn off the border over the main header (that you want to eliminate).
There is a setting for Headline Border ... which to me would mean the box in question. Turning it on and off has no affect at all on my schedule. The Header Border controls all headers including the tabel title (headline?).
So...you might be stuck masking things out with a white fill, or turning the header borders off and drawing in the borders you want manually. Sigh.
Karl