what I really want to know, was if anyone has managed to get a non-changeable ticket changed, and if so, in what circumstances they did it.
The only time I've managed it, is when I've turned up early for a flight, well before the previous flight had departed.
For operational reasons it was convenient for the airline to put me on the earlier flight, as my original flight was overbooked.
They offered, I didn't ask.
I don't expect you'll have any luck in changing this ticket, but your TA may have a deal with the airline that allows
them to change it.
bjorns