I flew last weekend from EWR to HNL and got mail a couple of weeks ahead of time from my travel agency with a new itinerary when the flight moved from 2:00 to 1:10. But when I got here, I found that several of my colleagues who had used a different agency (American Express corporate travel) were not notified and found out only on arrival at the airport or when they confirmed the flight that morning from home.

CO could certainly send emails to those people who have registered a FF number in the record and an email address for the FF number...