Hi Mark,

Starting with the Wizard, select the Address1 mergefield as the one to be
tested and for the condition use Equal to and put a 1 in the box next to it.
Then for the results, enter 2 and then 3.  Then click on OK.

Then press Alt+F9 to toggle on the field codes and you will see

{ IF { MERGEFIELD Address1 } = 1 "2" "3" }

Now, select the 1 and then insert the Address2 mergefield.  Then select the
"2" and in place of it, insert the Address1 mergefield, and in place of the
"3", insert the Address1 mergefield plus Shift+Enter for a new line and then
the Address2 mergefield

so that you end up with

{ IF { MERGEFIELD Address1 } = { MERGEFIELD Address2 } { MERGEFIELD
Address1 } { MERGEFIELD Address1 }
{ MERGEFIELD Address2 } }

Toggle of the field codes with Alt+F9.

All this goes in place of the Address1 and Address2 mergefields.  They
should not appear anywhere other than in the above field construction.

Please post any further questions or followup to the newsgroups for the
benefit of others who may be interested.  Unsolicited questions forwarded
directly to me will only be answered on a paid consulting basis.

Hope this helps
Doug Robbins - Word MVP