Thanks, Graham.  I should have given you more information.  I tried copying
and pasting the three lines of the return address into the search and replace
window, but that didn't work.  The reason I tried to do it that way was
because the spacing between those three lines is wide (it was emailed to me
and I just pasted it into my mail merge document - should have retyped it
instead) and I can't figure out how to fix it.  When I highlight it and
select paragraph, the line spacing already says "single," so I just wanted to
replace the weirdly spaced return address with a retyped return address that
is spaced correctly.  Hope this makes sense!