Originally Posted by Often1

DL agents have very little discretion to waive rules on E fares and DL has designed those to prohibit gaming the system, e.g., waiting to seat assignment and then determining whether it is worth paying up to the next available fare bucket. Some supervisors have that authority and may do this for high-level elites.

The toll-free number is -- well, toll-free -- so it costs nothing to call and ask. Saying that you did not read or understand the rules is a bad way to approach this. DL gets tons of those calls. I would simply approach this as a plain & simple business proposition and cut out the time-consuming fibbing. Just as whether you may pay up to the next available fare bucket and ask what that would cost.

As a general proposition, as you get closer to flight time, ticket costs increase. But, not always. If you are lucky enough to get past the first hurdle, e.g. changing a rigidly inflexible ticket, make sure that the price for the next available fare bucket is worth the cost.

At the same time, take a look at C+. Without knowing exactly what you paid and your itinerary, that may or may not be a major expense.

Don't get your hopes up here. But, do make a single well thought out call. DL agents are likely to note your PNR with any refusal, so calling back repeatedly won't get anywhere.

If all else fails, ask at check-in and the gate.