It is NOT possible. Were you ever able to scroll anything on a printed piece of paper??? (Really, not being sarcastic.) But, I hope this will be a clue as to the purpose of a report is to put things on paper.
Perhaps you may want to check out properties "Can Grow = yes" for the area you want to see bigger in your report. Else, you may want to work with a form and a memo field or sub form to get your scroll bars.