Padova's Adobe 8 Bible mentions a Page Size Toolbar, availlable through the Crop Toolbar. I cannot find such a device. I have a .pdf file which obviously originally was an Excel file, but the writer set it up as a letter size file rather than legal size, which would have been the logical thing. I can't find any way to edit the page size to legal size.
But you'll find the crop tool in the "Advanced" menu > Print production;)
abracadabraPDF.net