In OfficeRnD you have the option to enable RSVP for events. It allows you to track who is attending the events and to track the taken slots if there is a limit to the event slots.
How to activate RSVP?
Go to Settings > Member Apps > Member Pages.
Check the Events RSVP checkbox.
Click Update to save the change.
How to RSVP for events
RSVP in the members portal - If the Events RSVP function is enabled, members can respond to events in the Events module of the Members Portal.
RSVP in the mobile app - apart from being able to RSVP in the members portal, you can also use the app to do that. Tap Show All and select Events:
After that you'll be able to see the available events and RSVP for them:
How to check reservations
You can check who is 'going' or 'interested' in the Admin portal.