If you have a delay or cancellation, the App/DL.com re-booking engines will give you a number of airports within a radius (looks like 300 miles from post above). Easy to do once your flight has the underlying delay/cancel in it -- no need to "beg" an agent to make it happen provided your itinerary is in synch and has the right back end coding for IRROPs.
You can also change your departure airport in those scenarios (e.g., you are on LGA - RDU but you switch to JFK - GSO instead).
It usually gives you a laundry list of connection possibilities -- and, if you have time, there's usually an opportunity to turn it into an MR. I've never had time but have been offered routes like:
DTW - LAX - RDU when my DTW - RDU flight has been delayed (and there's an LAX - RDU redeye operating)
Always hold out hope they'll offer me something like DTW - CDG - RDU (which at times might get me home faster in really bad IRROPs) but it seems like the booking engine limits to domestic connections only (which is fair).
Last edited by Duke787; Dec 11, 2019 at 9:19 am