If you need to collect more than Yes or No responses, like Maybe or a specific Date and Time, we recommend using custom form questions to collect that information.
Under Setup > Registration, please confirm that the "Allow Guests to RSVP No / Not Attending" box is unchecked. By doing that, all potential attendees will be funneled to the RSVP form to complete it.
You can add custom questions to your registration form. We often have people set it up this way:
Question: Can you attend?
Multiple Choice: Yes, No, Maybe
Question: If you can attend, which time is best?
Multiple Choice: 9:00am, 10:00am, 11:00am
You can see these responses in your Attendee List or Attendees Report to sort responses or send appropriate information.