This afternoon I was flying MSP-ORD on a United Express E175 flight. I received my CPU at T-72, and I checked in before I went to bed last night.

When I woke up this morning I had received a text message from United: "you have a new seat due to an aircraft swap". I checked the app and, sure enough, I am now sitting in E (not E+). Curiously, the seat map is for the same plane type as originally scheduled - the E175. My ticket is still shown as fare class R. And, only 3 of the 12 seats in F are taken.

Using the app, I try to change my seat. It lets me select a seat in F, but then it won't close the deal - it says seat selection can't be confirmed.

Call Premier line, explain situation. Agent confirms I'm in fare class R, but she can't assign me a seat either - it sounded like she was having the same issue I was having.

Go to airport. By the time I get to the gate, I note that (a) the upgrade list has about 30 people on it (really unusual in my experience for the MSP-ORD route), (b) I am not on the upgrade list, (c) there are still 8 open seats in F, and (d) the GA is starting to call names off the top of the upgrade list.

Uh-oh... But it ended well; I got the GA's attention, explained the situation. She said it looked like I wasn't actually checked in to the flight, which was odd since I had a boarding pass for an E seat on my phone... But she was able to print me a boarding pass for a seat in F.

Still, it was a really odd turn of events. Anybody seen something like this before? Any idea what happened, or does it fall into the "random IT glitch" bucket?

Never heard of this - but surprised the phone agent didn't just re-check you in. Isn't that the equivalent of "have you tried turning it off and on again?".

I've found basically any change after check-in should start with checking in again.

If you can successfully check in and accomplish whatever you wanted to great! Cobweb broken free, problem solved. Total investment less than a minute.

If you can't successfully check in and accomplish whatever you wanted to something is really screwed up and allow plenty of time and persistence to get someone to understand what's wrong and fix it.

The equipment swap screwed up your prior online check-in. Though not all agents know to do this, the proper way to handle it is to undo your existing check-in, then check in again. At that point, you should have been able to pick a F seat.

I have no real explanation for why the system behaves that way, but IME that is exactly what happens and what you have to do to fix it.

Thanks for the tip.

Of course, it's not clear to me that there really was an equipment swap here! When I checked in originally, the plane was an E175; and the actual plane today was an E175. Oh well...

While frame swaps usually don't cause seat assignments to drop, sometimes they seem to (and other times I get an equipment change EF trigger even though my seat is intact). Maybe someone fat-fingered E70 instead of E7W on the computer before fixing it. Could be anything.

I've seen this when there was a down gauge but the final new frame wasn't in the system. I've also seen a legit equipment swap force a need to un-check-in and redo it as the above post notes.

either way, grab a screen shoot showing confirmed R...just in case.

Close - first they turned it into a CRJ-200, then to an E70. Then back to an E7W a few hours later (Time is local MSP/ORD time) :

Aug 8 3:57 AM AEQP Changed From E7W To CR2
Aug 8 3:58 AM AEQP Changed From CR2 To E70
Aug 8 6:04 AM AEQP Changed From E70 To E7W

Very interesting. The timestamp on the text message was 4:06am, by the way.

This has absolutely happened to me on an aircraft swap, though not the CPU impact because I was in paid C. With that said, two separate phone agents were unable to check me in because the flight had gone from a 2 cabin to a 3 cabin and it wanted to add me to the upgrade list but due to whatever backward IT system they have it just couldn't do it. 1K agent on the phone was great and tried everything down to reissuing the ticket and then trying to check me in to no avail. It was a definitely a conflict with the CPU list causing the issue because my fiance on the same itinerary that had been split was checked in just fine (she has no status and had been separated from my status via the PNR split). It took an agent at SFO at least 15 minutes to get me checked in for that flight and she could only do it by taking me off the upgrade list and then putting me back on it after checking me in.

I'm sure the front line just loves these gremlins.