Originally Posted by ATOBTTR

Again, what are you trying to get out of this? If what you're trying to get is to be moved to the flight that is now operating at or close to your original flight time, that shouldn't be an issue and is within DL policy and you could probably even manage this online and not even need to call, except for a few circumstance. But of course there are caveats. How did you purchase this ticket? Was it booked directly through DL with cash? Through a partner? Third party site? Booked with miles? Partner miles? Also, who is operating the flight you're trying to switch to? ETA: I see above where you gave the flight numbers and both are DL-operated. Other questions remain.

Second, if you're trying to get your original seat back on the original flight, while admittedly frustrating and even infuriating, unfortunately they will continue to tell you there's nothing they can do, seat assignments are not guaranteed, etc. ETA: You noted wanting an aisle seat in the forward section. The 9:55 PM flight has plenty of "Preferred" aisle seats available in the forward section (and so does the 11:50 PM you're currently on) which you should be able to select as a PM unless you don't have your PM status attached to this reservation for some reason.

Your frustration may well be justified but more details are needed so others here can properly advise you on what you can or should be able to do and advise whether you've just hit an unfortunate stretch of bad agents or if there's something more complex going on.