Once the event registration page has been created, you are not able to go back and change the appeal (or add an appeal) to the registration page. We would like the ability to either adjust or add the appeal after the registration page has been created.
The Event Registration Form allows addition deletion and edits to Appeals associated with the Event used on the Form. In order to enable the appeal tracking option, the part must contain at least one paid event. If you require an Appeal to be associated for free event registrations, we advise adding a paid option to the event in CRM, but not including it on the event registration form.