Assuming you are feferring to your primary Comcast email address--------you can't close it. It is your sign-in credential for all things Comcast on the internet. You can change it if you like, but you have to have a user ID. That said, nothing requires that you use your Comcast email address as your main email action. You can use email from any email provider you like----------Yahoo, Outlook.com, Mail.com, Gmail, and the list goes on.