How are you reducing the page size, and what version of Word are you using?
When you say it "loses the text", what is happening? Is the text being cut
off at the margins? When you reduce the page size, are you not reducing the
margins, accordingly, as well? If you are reducing the outer dimensions of
the page, but are not adjusting the text so that it fits within the
printable region of the printer, then one would expect for the text to be
cut off. If the page/paper settings are set up correctly, however, Word
should be warning you that that is going to happen, though. Hence, to help,
more information on exactly what you're doing is needed, since Word should
be handling the details if you're using one of the built-in methods.