Multiple ticket numbers on single PNR
 

Early in the Cabotage thread, there is this statement:

So, I looked at a recent six-segment ticket of mine. It looks nothing like that.

The receipt has ticket number 016-XXXXXXX765. The other boarding passes say:

Segment 1: 016-XXXXXXX766
Segment 2: 016-XXXXXXX653
Segment 3: 016-XXXXXXX653
Segment 4: 016-XXXXXXX653
Segment 5: 016-XXXXXXX664
Segment 6: 016-XXXXXXX766

Is this some peculiarity of fare construction? (i.e. 1 and 6 form an open jaw, 2-4 are a one way, and 5 is another one way? Fare bases were Z,D (ON),D,Z,Z,Z. My destination was 3.

I'm obviously confused. I previously thought a PNR meant one ticket and one ticket number. Clearly I have a lot to learn. Can some kind soul explain the difference between ticket, ticket number, and if relevant how this relates to fare construction.

Every traveler has a separate ticket. A PNR can have multiple travelers on it. Therefore, a PNR can contain multiple tickets.

That's right, tickets and reservations often do not have a 1:1 mapping, particularly when you (1) involve multiple carriers, (2) have many segments, or (3) make changes.

Have a look at IATA Resolution 722f. Off the top of my head, I think there's some tortured accounting that gives you up to 16 flights per e-ticket number. (A direct flight, e.g. SQ61 IAH-DME + SQ61 DME-SIN, counts as a single flight.) This can be expressed as "16 coupons per e-ticket" or something baffling like "4 consecutive tickets, each containing up to 4 coupons, per e-ticket".

So if you want a PNR with >16 flights you'll need two e-ticket numbers. Hooray.

Some UA-related ways you can end up with multiple ticket numbers:

(1) When UA issues award tickets that involve travel on partner carriers, they sometimes create some extra "conjunction tickets" for each separate carrier, sometimes as many as one per extra carrier, meaning that a simple IAD-FRA-CDG trip might have a UA e-ticket number covering UA IAD-FRA and a UA e-ticket number covering LH IAD-FRA. Can usually spot these conjunction tickets because the # is 1 digit higher than the base ticket and because when you look it up you're shown the base ticket number.

(2) If you make a change to your trip after it has begun, the old e-ticket will show some portions "flown" and some portions "refunded"; the new e-ticket will only contain the new segments and will eventually show those "flown". Both the old and new ticket definitely need to be attached to the PNR for accounting purposes but only one is actively in use for travel.

(3) If you make certain kinds of irrops-related changes to your trip, you may get a "single coupon exchange" which results in a brand new e-ticket being issued to cover only one of your segments. I've had a FRA-SIN // SIN-HKG // HKG-FRA flight with 1 e-ticket covering all 3 sectors; after some irrops, UA rebooked SIN-HKG on SQ and I ended up with one e-ticket that just had SIN-HKG on it ("open for use") and another e-ticket that had HKG-FRA on it ("open for use").

To understand this stuff better, become a travel agent (and let me know if you can find an affordable way to become a home-based travel agent / get your own GDS access…)

It would be very unusual for you to to end up with that sequence of ticket numbers naturally for a ticket booked on united.com. Normally it would all be ticketed on the same ticket. Did you encounter irrops at any point during that itinerary? The GPU upgrade shouldn't have triggered a new ticket number unless agent intervention was necessary for some reason, but if you encountered irrops or an agent manually reissued your ticket for some reason, then it wouldn't surprise me if they exchanged a portion of your itinerary and left a different portion on the other ticket. It often seems fairly haphazard which segments on a complex ticket they reissue.

That depends on your definition of affordable. When I first started a while back I used Nexion (http://www.nexion.com). It's $55/month plus non-trivial setup fees (looks like $288 in all), and they expect you to have some experience with the GDS. Sabre also has a direct offering for searching availability and doing some basic tasks, but you can't issue tickets with it so it has very limited usefulness.

A PNR even for a single traveler can have multiple tickets as well, although barring irrops United generally won't do this directly (but any travel agent can).

I did an SDC on the 1st segment to catch an earlier flight. The original BP has the same ticket number on it, though.

Segment 5 was overbooked, and United tried (but not very hard) to convince me to take an alternate flight. At one point, both the actual and the alternate were on my reservation, but I had the BP's for 5 and 6 in hand at that point.

I had just had two UA legs and one LH leg with the return in a few weeks of two LH legs. It is all one 016 ticket with one PNR/confirmation/booking reference for the UA legs and a separate LH PNR for the LH legs.

If one reservation, one 016 ticket number. If separate reservation numbers then different 016 ticket numbers.

However, if you have two pax on the same reservation, then one PNR but two 016 ticket numbers.

Yup. Each pax gets a separate ticket, but multiple segments for one passenger that are fared together by UA will all be same ticket.