Logged in with an email address:
To update your email address, please log into your account, select “My Account” from the pull down menu, and click on “Account Settings” on the left side of the screen. You will then be able to click “Change Email” and enter your new email address.*
Logged in via Facebook:
You would have to change the email address in your Facebook settings.
*Don't see "Change Email" on this page? If you created your account via Gmail, you cannot edit/change your linked account. Please cancel your current subscription and sign up again under your desired email address.