Got it today from NW. let's see if it works:

Thank you for contacting Northwest Airlines regarding a possible upgrade
of your WorldPerks account to an Elite status.

While you did not accumulate the necessary mileage credit through the
Northwest WorldPerks program, we would like to review your flight
activity for a possible exception. Please forward actual copies of your
most recent Delta and United Airlines mileage statements for the past
two months. We will also accept a copy of your latest six months online
Delta and United Airlines activity, provided your year-to-date Elite
qualifying miles are included.

Please send this information to:

WorldPerks Customer Service Center
Attn: Emily Hayes
601 Oak St
Chisholm MN 55719-1995

Or via fax at 218-254-7567

Please be advised that we are unable to accept the following forms of
documentation--travel agency reports, letters of Elite status,
membership cards indicating Elite status with another airline, or travel
itineraries.

Please also note, for security measures, we are not able to access or
open attachments/scanned material.

We appreciate your interest in the WorldPerks program and would consider
it a privilege to serve your future air travel needs.

If you have any additional questions, concerns, or need further
assistance, please let us know.

Sincerely,

Lee Braaten
WorldPerks Customer Service Center