Yes, I acknowledged they have discretion. So your claim that you were told the policy was the same state or 500 miles is equally likely to have been made up. If you have some policy document that says otherwise, rather than saying the one I identified is wrong, it would be useful.

Nonetheless, you still have not controverted the main point: the OP is bemoaning the lack of the ability to do a self-service change to a city 450 miles a way- something that just doesn't exist. I also wouldnt be surprised if the self-service rebooking tool has specific permissible alternate cities coded for each destination, and doesnt do a mileage calculation each time. Given how many airports served by DL are closer to RIC than JFK (ORF, DCA, IAD, BWI, RDU, GSO, PHL,,MDT, CLT, MYR, PIT) I wouldnt expect it to appear on that list