The only times I've seen DL proactively allow you to switch without going to the airport is when they call you, and the only time I've heard about them calling you seems to be when there is an equipment swap and they lose a lot of seats and are now not oversold by 1-8 (what they appear to be comfortable overselling most domestic flights) but now are oversold by 30-40 and it would be chaos at the airport.

Co-terminal SDC is highly unlikely to be authorized for non DM's.

I'd absolutely call and inquire if they'd do a courtesy swap, but I would not be expecting it to happen, as reasonable as your case may be.

TLDR; you will either need to pay to switch your flights, or go to LGA and try for VDB but expect to fly.

Looks like DL is only selling 2 more seats in Y and 3 in F using a dummy booking. I don't have access to EF so don't know the real loads. I'd say it's pretty likely that they'll need to VDB by tomorrow.

5 empty seats still? The flight will probably even out as there may be misconnects or pax who oversleep.

Things can literally change by the minute but in my experience I wouldn't call this likely to VDB by tomorrow.

It very well could even but yesterday someone reported it was Y6 and F3. Mabye I overstated that its likely that they will need VDB but there's a good chance that a VDB. The flight the OP is taking is a night flight so don't think anyone will oversleep but you never know. ;)

Currently:

DL 840 LGA 07/20/17 6:59 PM PBI 07/20/17 10:14 PM 319

50% / 96m F2 P1 A0 G0 W0 Y2 B1 M1 H0 Q0 K0 L0 U0 T0 X0 V0 E0

You can always call and ask, and there's a reasonable chance theyd' move you under an exception w/ SDC .. however you wouldn't get compensated. It might be worth the time / hassle to just show up and potentially clip $400-800 each or whatever!

Your flight is currently:

DL 840 LGA 07/20/17 6:59 PM PBI 07/20/17 10:14 PM 319

F1 P0 A0 G0 W0 Y0 B0 M0 H0 Q0 K0 L0 U0 T0 X0 V0 E0

Good luck, and DO let us know what happens! :)

I'm the OP-

So here is the final outcome. Got a call about three hours pre-departure to call Delta because the flight was delayed. The delay was only about a half hour. I basically begged the platinum line agent to put us on a flight the next day (tomorrow). He was sympathetic and agreed; we are now on the 1030 flight confirmed in bulkhead comfort A&C (no one in B) and are number one and two on the upgrade list with four available in FC. Basically, as good an outcome as I could've hoped for assuming no giant VDB offer. And we offer. And we didn't even have to go to the airport :-)

It's a pleasure to work with a representative who truly tries to satisfy the customers;. I actually told him that I was in the middle of teaching a class with a room full of doctors when the call came and I would sing Delta's praises; which I did. Win-win for everyone.

Congrats! Glad you had a great outcome.

But - - they CALLED YOU for a half hour delay?!?!? :confused:

Texted me to call them! I deleted it but it was something like "there will be a delay in your flight number XX for this evening. Please contact DELTA." I can't remember whether it said something about alternate options. When I spoke to the representative, and said that, quite frankly, I was hoping that the delay would be Long enough so I would be able to reschedule for the flight tomorrow he said "no problem; and we talked about what the availability was on various flights".
I know, pretty funny given how many times the schedule shows no delay 20 minutes before I arrive at the airport and then we wait hours and hours while there....

Well, it looks like it was delayed almost two hours leaving, but only an hour and 6 minutes late arriving. Maybe the phone agent knew something that you didn't.

:)

Thank goodness I wasn't in that middle EC seat. Major knee problems... would have been tough to drive afterwards ( assuming some of the delay was w pax on board).
Thanks for the follow up.

Final outcome-
Both of us were upgraded to first class, and with a little (politely asked, and happily agreed to) trading, ended up in one a and 1B. Took off on time, but lots of weather problems although we managed to land between storm frontS and ended up only about a half hour late. Cuban sandwich lunch: I thoroughly enjoyed it, my partner did not. Overall, a great outcome for us.