You can change the travel date for a domestic ANA Flight Award ticket:  1- Up to 24 hours before your new flight’s departure date, and  2- Before your original flight’s departure time  However, you are not allowed to:  1- Change to a flight that departs earlier on the same sector after arriving at the airport on the day of travel.  2- Change your ticket to a Blackout Date. If your date change impacts an award ticket’s seasonality, ANA will adjust your mileage per rules.