Yes it's possible if your printer doesn't choke on it.  Click on Tools |
Options | Print | check the "Allow A4/Letter paper resizing" box.  How
it works is:

1.  If letter-size paper is chosen in File | Page Setup, and if
letter-size paper is chosen in File | Print | Properties, then the
document prints normally without resizing.  Same thing if A4-size paper
is chosen in both places.

2.  If letter-size paper is chosen in File | Page Setup, and if A4-size
paper is chosen in File | Print | Properties, or vice versa, then the
margins of the printed pages are adjusted automatically.  To my eye, the
printed text area appears slightly shrunken when going from one paper
size to another, but every line begins/ends in the same place and there
are the same number of lines on each page.  If you start out with 1"
margins all the way around in File | Page Setup, a letter-size document
printed to A4-size paper has larger top and bottom margins than the the
original, and an A4-size document printed to letter-size paper has
larger left and right margins than the original.

Hope this helps.