See http://word.mvps.org/FAQs/Formatting/WorkWithSections.htm (toward the
end).

As you've found, you can't simply remove the section break because section
breaks store all the page layout information for the section *above* the
break. For a full explanation and instructions for how to get rid of a
section break at the end of the document see here:

http://www.word.mvps.org/faqs/formatting/WorkWithSections.htm

In your document, if page 2 is not completely full, you might be able to get
away with just changing the last section to be continuous start - put your
cursor at the end of the document and use File > Page setup > Layout to
change the section start.

--
Margaret Aldis - Microsoft Word MVP

There are a couple of things that may work. Turn on Show Paragraphs, and
look for a paragraph mark on page 3; delete it if you find it and this
should make to section break superfluous.

If this fails, select all the text down to but NOT INCLUDING the section
break; copy and paste it to a new document.