Visit Delta's website. Click "SkyMiles Login" from the left side of the page.
Enter your Sky Miles number or email, PIN and last name in the applicable text boxes. Click the red "Log In" button.
Move your mouse over "SkyMiles" and click "Manage My Account." Click the blue "Manage Profile" link at the top center of the page.
Edit your profile information by clicking the type of information you wish to edit at the top, such as "About me" or "Credit Card" and clicking the red "Edit" button underneath the section you wish to edit. After entering the new information, click the red "Submit" button.