Open your chat tab on the app and go to your chat group
For your event click on View all responses
Click on the No Response Tab to view a list of those who have not RSVP'd yet.
Click on Resend event to Not Responded list to initiate a resending of the event invite.
Note: The resend can only be completed once. Anyone who has already RSVP'd will not get the message prompting them for a response.