To change your email address or password on your Earnest profile, sign in to your account. Click on your name in the top right corner of your dashboard. Under Account Settings select the "Email & Password" tab from the menu on the left to update the desired field. If directed to a new screen, click “Edit” next to the option you wish to change. Be sure to click "Update Email/Password" or “Save Changes” when you're done to ensure your updates are saved.
See also, How to Reset Your Password.