Change your username by selecting your name at the top right of the page followed by Settings in the drop-down menu. A field for your Email Address/Username will display on the next page with your current address listed. To change your username, delete what is currently listed and enter a new username. It is important to note that the username MUST be an email address in order to be accepted by the application. After the new username is entered, select Save at the bottom of the page. This will be the username/email address you enter when logging in from then on.
Note that this will not change the email address that is displayed on your card. The two can be completely different addresses. All Refer.com notifications and correspondence will ‘go to’ and ‘come from’ your username email.