Friends Asking Friends (FAF) event have the capability for a previous participant to log in with the same username and password as the previous event. The Autofill function will auto populate their login and/or contact information into the form. However, the supporter is unable to edit their grayed out autofilled information within the form.
To edit this information, you will want to mark the Unlock autofilled form and allow me to modify my profile checkbox at the top of the form. From there, the contact information will no longer be grayed out and be editable.