Tip: How to Find United MileagePlus Award Partner Confirmation Numbers

As experienced travelers know, choosing your seat in advance can make a big difference in the flying experience. For some cabins — like Finnair's business class and Aer Lingus' business class — it can mean the difference between having a row to yourself or having to share the same space with another passenger.

However, in order to select a seat, you usually need to work with the operating carrier to request it. A key requirement for retrieving your flight with the operating carrier is having the confirmation number from that airline, which usually differs from the confirmation number of the airline through which you booked the flight.

I ran into this issue when trying to check-in for my recent Austrian business-class flight. While I was able to get a quick response from a United Twitter agent, a couple of commenters pointed out two easier ways of retrieving this confirmation number with the carrier. Turns out, this information is hiding in plain sight. Here's how to find it:

United Website

1. Log into your United account.

2. Scroll down to Current Reservations and select View on the flight you're interested in.

3. Under the United Confirmation Number banner, there's a smaller line that'll say, "This reservation contains partner flights" with a link to "View additional confirmation numbers." Click on this link to reveal the partner confirmation numbers.

United App

1. Open the United app and select My Reservations from the top menu.

2. Select the booking you want to retrieve the confirmation for.

3. Scroll to the bottom and select "Additional information" to reveal the additional confirmation numbers.