1) First, make sure you are logged into the parents account.
2) Go to the "GROWNUPS" bottom on the top right of the homepage to access the drop down menu and click on the "Membership" button.
3) Click on the "Profile Details" button on the left side of the screen. There will be a textbox with your existing email address that is attached to the account.
4) Input your new email address. After you have changed your email address just click the, "Update Profile Settings" button to save your changes.