To edit invitations or manually change a guest’s status after the event is closed, go to your Event > Guest List Management > Guest List > select the guest > Guest Invitation. Under their field information is Guests per Invitation, select to increase or decrease the number of invitations to the event, and change status.
Changing a guest’s status to confirmed will not send them a confirmation email. To send a confirmation email, select the guest in Guest List, then Re-Send Confirmation.