PATH 1
You will see your RSVP answers on the top right corner of the event detail page. Click on the answer.
A modal window opens. You can edit your answer on this window. Click Submit when you are done.
PATH 2
You can also go to your RSVP answer on the Attendees page. Click the three-dot menu next to your name and select your action.
Edit opens your current answer and allows you to edit the content of your answer.
You can also quickly change your RSVP answer by selecting a new answer.
You can also Delete your RSVP from this interface.