Activate a new Macy's credit card through the Macy's website, as of May 2015. Provide your account number, and if needed, the last four digits of your Social Security number as well as the card protection numbers from your old and new cards.
Once a customer gets confirmation of card activation, he can add the card to his profile. The process to activate the Macy's American Express credit card is similar. To find activation links, customers should navigate to Macys.com and choose Macy's Credit Card at the bottom of the page. On the left side of the resulting page, they should click on Activate Your Card, and they can choose between the Macy's credit card and the American Express card.