Well, a friend did this...

He called AA a few weeks earlier and asked about changing his dates. They said no dice. On my advice, he tried a different telephone number, but no dice.

I suggested trying a "dead grandmother." Thinking it was a good idea, he called them with a very sad voice. They were quick to mention, "Well, on my computer screen, you called twice and had already said you changed your mind. Now do you want to try the dead grandmother routine?"

Needless to say, he was stuck on the original flight.