Select the reference time trigger event for sending the email.This setting works with the Trigger Time Offset setting and Trigger Window settings to determine when the email action will trigger. *"Booking" will trigger within the selected trigger time and time window after the booking was made regardless if the guest has already checked-in at that date. *"Booking (but not after Check-in)" will trigger within the selected trigger time and time window after the booking was made until check-in (not after check-in). *"Check-in" will trigger at 00:00 on the check-in date of the booking. *"Check-out" will trigger at 00:00 on the check-out date of the booking. Note '''Check-in''' requires a negative Trigger Time to set the trigger time before check-in. A positive Trigger Time will be senttrigger that long after check-in.