pewpew

Whenever there's a change to your itinerary, voluntary or involuntary, it never hurts to look at the cost of booking a new ticket. Even within 24 hours (the standard fee-free change/cancelation period), there can be a decent fare difference in your favour.

For example: I wanted to make a change to an itinerary within 24 hours of booking it. The fare rules stated that any changes resulting in a lower cost forfeited the residual value, while those with a higher cost required the difference to be collected. The new itinerary was $20.75 cheaper; however, if I'd simply made the change, I would have received $0. By canceling and rebooking, I received the fare difference. It took perhaps an extra five minutes to search for the cost difference and cancel and rebook.

Similarly, when there is a major schedule change, you're given the option of canceling or rebooking. Same thing: if the new itinerary is cheaper, you won't see any of the difference; however, if you cancel and rebook, you will receive the fare difference.

It's something most of you here probably know, but it never hurts to be reminded of.

MSPeconomist

The same issue can arise with reroutings during IROPs. For example, DL currently is pricing its TPAC flights with connections through SEA much more cheaply (by thousands of dollars on some business class fares) than, for example, DTW (or MSP, JFK, ATL, and even LAX routings). If you let DL rebook you through SEA, there will be no refund and you might experience not only less desirable schedules but also inferior aircraft (for example, a 767 rather than a 747, 777, or A330, where most people would consider the 767 to be much less comfortable in business class).