I recently put together a digital book in pdf form and I'm in the process of getting it ready for paperback printing. However, I originally formatted the book with a page size of 8.5" by 11" and now I want to change the size to 6" by 9" since that is the most common trim size. What would be the most efficient way to reformat the book for this new trim size? It's a long book at over 450 pages so I would like to automatically format it as much as I can. I tried changing the page sizes in acrobat and word but the text doesn't change along with the page size in those programs. Let me know if I'm missing any steps in those programs or if there's another way.