They may very well be right about not having enough time. Your friend it travelling TODAY, and in order for them to re-ticket, they will have to put it in the automated queue, which they generally don't do on day of departure. Have your friend explain their situation at the airport. Tell them to say "I didn't see the schedule change until I checked in online today, and the folks on the phone said they wouldn't have time to re-ticket it before I left, so they told me to ask you guys". All but the most harried ticketing agents will likely do the change for them.