Go to EventON RSVP settings > Reminders
You can set up reminders for types of attendees. Keep in mind the reminders function use wordpress Cron-jobs to send out emails, so the emailing might not get sent out at the exact time, but little later.
Once you set reminders within Reminder Settings, you will see option to enable them for individual events, in event edit page under RSVP box.
Go to EventON Tickets settings > Reminders
Similar way as above you can configure which reminders to take place in reminder settings for tickets.
Once you set reminders within tickets Reminder Settings, you will see option to enable them for individual events, in event edit page under Tickets box.
More Documentation: http://docs.myeventon.com/documentation/addons/reminders/
Requirements: EventON and RSVP Addon OR Tickets Addon