I called into Delta this morning to switch my flight from one leaving Lansing at 1:30pm and getting into JFK at 6 something to one leaving at 10:46am and getting in at 3:30pm. If you call 3 hours before a flight, the fee to switch is only $25.

The reservation agent (what is the preferred nomenclature these days? Schedule engineer?) told me that no seats were available.

I called back two minutes later, and got connected to a better reservation agent, who took care of getting me booked on the earlier flight.