I recently purchased an all CO itinerary from NW due to pricing and the fact that I had a flight credit from a NW trip that I never took. It was all CO metal, but w/ NW code-share numbers. For example (not real #'s) CO23 as NW6023, CO140 as NW7140, etc. So, I have a NW PNR w/ NW flight #s and then a CO created their own PNR w/ CO flight #s. I don't know why, but they did...

Anyway, I finished up early and called CO to see about earlier flights... they directed me to NW since that's where I purchased the ticket. The agent said that they didn't have access to the fare quoted, class of service, etc etc etc... I thanked him, hung up called back and was told the same thing by another agent.

So, here's where it gets interesting. I call NW and they tell me that I never took my original flights and that all of my downline flights have been cancelled, and NO I can't get an earlier flight because I wasn't even on the flights that mysteriously got me to this city. The NW PNR says that I didn't take NW6023 because I took CO23 on the CO PNR, as far as they're concerned I never took a flight from the NW PNR.

But, when I call into CO they say that everything is fine for my downline flights, and they don't understand why NW would tell me that they were cancelled... of course, the CO agent is looking at the CO PNR, not the NW one... I even went to the airport much later in the day after returning a rental car and was told by CO that everything is just fine for my original flights...

I call NW back and they tell me flat out no, my flights are cancelled and there's nothing I can do about it... and again, no I can't change to a later flight because I never took NW6023, even though I did take CO23. They don't care about my CO PNR because they didn't price and/or ticket that one, so there's no way for them to change it, I need to call CO for that of course CO disavows any knowledge of my fare basis, etc...

I've seen this once before... it seems that if you book an all CO leg as NW code-shares that CO creates their own PNR for that leg, or trip. But, then that screws up the rest of your NW itinerary if you have one. Since, when you check in for your flight, you aren't on the NW PNR w/ NW code-share flight numbers, but a separate CO PNR w/ CO flight numbers...

It turns out that the flight I wanted to get onto was sold out anyway, so this was a useless point, but I am perplexed... has anyone seen this before?

I've never heard of anything like this.

So it seems that:
(1) You had an NW ticket for an itinerary that was all NW flights operated by CO.
(2) CO creates a second PNR for you--based on your NW PNR--with their flight numbers rather than the NW code-share numbers.
(3) NW somehow mistakenly believes that you simply didn't use your NW ticket for the first leg of your itinerary (maybe you bought a ticket for the same itinerary directly from CO, but as far as NW is concerned this is immaterial), so they cancel your NW PNR.
(4) CO has their own PNR for you, which they acknowledge does not contain fare info, etc. since they know it was created by NW, but they (CO) do not know that NW has cancelled your NW PNR, and they (CO) also know that you have taken the flights as planned, so CO lets you fly out your ticket as planned originally planned.

So, if NW is convinced that you didn't use your ticket with them (and, in fact, they won't even believe you that you did) can't you then apply the money that you paid for the NW ticket towards another ticket on NW--even though you actually flew all the flights for the original ticket?

The ticket was purchased from NW using CO metal and NW flight numbers.

Since CO operates the flights, a PNR must be generated in the CO system for processing your flights (check-in, etc.)

NW is not going to see that you took the flights on CO because when you check in with CO, no information is transmitted to NW about your flights on CO. If you had a CO to NW connection, then information would be generated in NW's copy of the PNR. I don't see why your reservation would have been cancelled, though.

Regarding re-using the ticket, the E-ticket would show used (if it was an e-ticket) or you'd be asked to turn in the paper tickets toward the future flight (if it was paper).

I'd be interested to know your PNR locator to check into this and send it to the NW automation department.

And FYI. CO can access the NW PNR and see what fare you paid, what the rules are, etc. Hell, even someone from DL can pull up NW fare rules and tell you the change fee!

This all seems fairly normal to me. I had the opposite experience (CO ticketed all NW flights ticket). I had a CO PNR and a NW PNR. All sorts of strange things happened as a result. Seat selection on the CO website didn't work correctly. Itinierary viewing on the NW website (using the NW PNR) worked, but seat assignments weren't viewable. I couldn't use the e-ticket kiosks to check in on either outbound or return, but desk checkin worked without a hitch.

What did work was EUA (of course that's the NW EUA that worked).

The previous flight credit that I wound up not using consisted of the following. (2) NW segment operated by CO as code-shares, then (2) NW flights operated by NW.

So, the outbound was (2) CO metal flights w/ their own PNR on the CO system. Are you saying that after I took those and showed up for my return trip that NW would then say "no you didn't take your NW flights and your NW downline flights are cancelled."

Besides keeping your boarding passes and putting up a fight, how would you make sure that your downline flights don't get cancelled in the NW system?

I've done this a few times where the NW code-shares are cheaper that the CO designated flights. In short, buying the same itinerary from NW is much cheaper than CO, or allows for a better routing and/or aircraft choices. It seems that if you entire trip is operated on CO metal booked as NW code-shares then you're fine, just ignore the NW PNR. But if you have a "split ticket" w/ the NW code-shares and CO metal on the return you're in for a rude awakening when you arrive at the airport for your return trip.

FWIW the CO PNR did upgrade me via EUA on some segments based upon my Elite status.

That's good to know--flying a NW itinerary tomorrow with CO metal on the outbound, returning on +NW metal--Was that an EUA based on your CO status?

I seemed that way to me.

I guess my only concern would be that NW actually shows that you took your outbound flights. If you can, when you get to your destination, it might not be a bad idea to walk over to the NW ticket desk and ask them (with boarding passes in hand).

I did go over to the NW desk yesterday and have them look at my itinerary. Basically the agent said that he didn't understand why it cancelled and there must have been "a glitch" in the system.