I think it's the form that pops up AFTER you accept the offer on the portal. Log in, and click to respond to the offer. After you accept it, it'll return to a new page an on that page is additional info stating "Congratulations on your acceptance to the Feinberg School of Medicine. We are delighted that you have accepted our offer. To confirm your acceptance of this offer, please print, complete and fax your
Acceptance Confirmation Form to 312-503-0550, or mail to Northwestern University, Feinberg School of Medicine, 303 East Chicago Avenue, M1-606, Chicago, IL 60611."
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