Flying to ZRH a week from today and have a PNR with two passengers. The flight is currently I0 so when I called the two of us are on the wait list (I'm SE the other pax is an E). The flight is currently J4, so am hopeful.

However, I am wondering what happens it the flight becomes I1. Does it give the I seat to the first person on the standby list with 1 passenger and possibly pass by me, or does it upgrade the SE and leave the E on standby?

When the agent thought it might be I1 she was willing to split the itinerary to complete one upgrade, but when she saw it was I0, she said it wasn't necessary and wouldn't do it. Anyone have the official answer?

It may be answered somewhere in history, but my search came up blank. Thanks.