So I'm traveling next week MSY-DTW-BWI. I paid for FC on MSY-DTW but Y for DTW-BWI. If I want to SDC, which rules will prevail, rules for FC or for Y? Not sure it's needed, but I"m in a G and L fare, respectively. Thanks for any help.

if DTW-BWI is on a single-cabin jet (CRJ200 or ERJ145) the FC rules will apply for the whole itinerary (although you may have to request supervisor intervention)

Thanks JR. Good point, no, DTW-BWI is a 2 cabin 737.... does that change the answer? thanks.

Do you know if you have a broken fare or not?

If your fare from MSY all the way through to BWI is an Lxxxx-wnup fare then you might be in luck as even if you are not in F for the DTW/BWI segment technically you may be entitled to it. and it could fall under the J/F SDC policy.

If it is broken fare then I would imagine you would fall under both. The MSY/DTW would only need F available but you would need L on the DTW/BWI segment for SDC.

Just my thought

If OP is in paid FC on some segment and coach on the other segment, how can this not be a broken fare? FC would need to be sold out but somehow delta.dumb permits purchase of a G A P fare? IME this hasn't happened and IIRC the fare rules have language about the instant upgrade fare requiring both coach and FC inventory in the correct buckets on each segment.

In the case of broken fares, the SDC rules apply to each flight separately and the routing cannot be changed.

But let's be honest . . . this is totally a YMMV situation from agent to agent. For instance, as a Diamond (me), I'd be shocked if I couldn't get a SDC worked out in this situation. As a Platinum, he'll probably have decent luck too.

(That being said, if it's an overnight+ stopover in DTW rather than just a layover, I'd expect any "rules" to be followed more carefully on the second leg.)

SDC for the FC flight? Yes, assuming that the new flight is selling a single FC seat. It should be easy.

SDC for the coach flight? The same inventory class needs to be available, although broken (domestic) fares allow "connections" exceeding four hours, which potentially results in more opportunities. The routing also cannot be changed.

This does happen on a regular basis. I booked a flight today, one segment in A and one segment in L, all covered by the same L-UP fare. Perhaps there just wasn't A inventory for the second segment, as when I tried to get FC all the way it kicked up to a P fare. The fare rules say you get an instant upgrade if available. If it's not available, the fare can still book into the coach fare class.

When I've been in that situation, I haven't been able to get delta.dumb to offer me a G A P fare.

maybe "delta.dumb" isn't as dumb as you seem to think it is ... you might try being nicer to it occasionally

OP here. thanks for all the replies. I chuckled when I read them b/c I'm now more confused then ever. (Kinda reminds me of moment in college when I asked a panel of three "science-types"/PhD's a SIMPLE question and got a PhD panel answer. I was so confused....

Alas, I'm more confused. So to reiterate, I've now checked and I'm on an A fare and an L fare. If I want to SDC and I'm ok keeping the routing the same, which fare rules will apply - the A fare class which means only a FC seat needs to be avail or the L fare class which means there needs to be specifically an L fare on the new flight I want? is the answer that the fare class will apply for each respective segment for which I'm attempting to SDC (i THINK that's what people are inferring?)

Also, finally, I'm not sure it matters at all but some have mentioned GAP fares on delta.com but I called the res agent when I bought up to FC so it was not (re)issued over the web, it was done w/ a res agent. Thanks for any further clarity.

My guess is that the system will focus on the A/L fare class, regardless of the actual underlying fare basis.

Here's why:
I once SDC'd a P fare where there were no FC seats available, but I wanted the new flight enough that I accepted a downgrade. Phone agent rebooked me into Y inventory. When I called again to "SDC" onto the same new flight in FC because a seat had opened, the new agent had to do some gymnastics because my ticket was now being governed by the Y booking rules, even though she could see the underlying FC fare basis. The new receipt I got was booked in F inventory, but the fare basis was still the same as my original P fare (I believe an H-UP).

Also, the fact that PAG booking codes drive the usual SDC rules and not the underlying HQKLUT-UP fare basis. Otherwise this forum would be filled with people struggling to SDC their FCM tickets.

So, you'll be able to SDC to any MSY-DTW flight with an open FC seat.

DTW-BWI will require L inventory to SDC, otherwise you'll have to SDS.

Also, YMMV, IANAL, AFAIK, LOL, YGTBKM, ASL, and TGIF.

I've gone over this several times. The best answer I have found is this:

If you purchased a ticket that had one flight with F and another with only one cabin then that ticket can SDC into F on both legs of a new flight pair.

If you purchased a ticket (as you did) where one leg was in F and the other in Y, you will not be able to SDC into F in both cabins, they will follow the rules for the two legs separately as if they were separate flights (even if you change cxn city).

I've gone through it both ways and been around a couple of times with agents and supervisors and that's been a consistent answer once I pushed to understand. The sense I got was the fare basis really is the guiding factor.

aha. got it! thanks to all those who replied. special thanks to Pater. I think I got it now. Phew!