Do note you don't need a macro for this; it can be done with an ordinary Find/Replace, where:
Find = ^p^p
Replace = ^p

Kilroy's wildcard Find/Replace macro will convert all instances of two or more paragraphs to single paragraphs. If your document's creator used 3 paragraph breaks, for example, to delineate paragraphs, you will lose that delineation.

After cleaning up the paired paragraph breaks used for the double-spacing, you might be interested in cleaning up even the unnecessary single paragraph breaks with the macro in this thread: http://www.msofficeforums.com/word/2...s-e-mails.html

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]