If you didn't set up automatic reminders when sending invitations, you can manually send a reminder to guests who haven't responded.
Steps
1. From GUEST MANAGEMENT, find the event. Select Actions → Send Multiple Invites.
2. Select the invitation template.
3. Click Customise to edit the email settings. Note: Only guests who haven't responded are listed.
4. Add 'REMINDER' to the subject line in the Customise Email dialogue. Click Update.
5. Click Apply To All, then Next.
6. Confirm recipients (all or specific), then click Next.
7. Preview and confirm, then click Send.
Outcome
Guests receive the original invitation email with 'REMINDER:' prefixed to the subject line.