If you want Word to reduce the pages for you automatically, your best bet is
to use the "2 pages per sheet" command in the Print dialog. You'll need to
work out the pagination manually, printing pages 32, 1, 2, 31, 30, 3, etc.
If you're willing to reformat, you can use the "Book fold" option in Page
Setup, and Word will do the imposition for you.