First, this is why travel insurance is always a good idea because if the change is caused by something outside of your control, it could very well be covered under your insurance.
But the change fees for some airlines aren't engraved in concrete and have been modified depending on the circumstances. For example, we had two couples on the cancelled Carnival Sunshine cruise and when they explained this to the airline, the airline only charged them one change fee for the two tickets instead of charging one change for each ticket.
But I appreciate what green_rd said about asking to be moved to an earlier flight. Had this happen just last week to a client. They got to the gate alot sooner than they thought and there was a flight leaving in 20 minutes, which was 2 hours earlier than their scheduled flight. The plane had 18 seats available but the airline would not allow them to get on that flight unless they paid $100 for each ticket as a change fee. Seriously? Obviously, they said no and just waited for their original flight, which turned out to be overbooked!! Gee, what's wrong with this picture?? It ended up costing the airline alot more money because of people getting bumped and it all could have been avoided with a little common sense. (Sorry, I realize common sense is a bad word.)