To Change Your E-mail Address

1. Go to Your Account.
2. Click Change Name, E-mail Address, or Password in the Settings section.
3. Sign in using the e-mail address and password currently associated with your account.
4. Click Edit next to the e-mail address.
5. Provide your new e-mail address and click the Save Changes button.

To Remove a Credit Card

1. Go to Your Account.
2. Click Manage Payment Options in the Payment section.
3. Sign in using the e-mail address and password associated with your account.
4. Click the Delete button next to the card you want to remove.
5. Click the Confirm button.

Link of Reference : //www.amazon.com/gp/help/customer/display.html?nodeId=565164