A Comprehensive Guide to United Airlines’ Same Day Flight Change

Mar 20, 2019

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Not boarding the flight you paid for can sound like the start of a travel disaster — unless you use “SDC” as a verb.

That’s short for “same-day change,” an airline option to replace your original reservation with a new, confirmed reservation on a different itinerary to the same destination. Most airlines allow some form of this, often free to elites, and it is worth learning their rules. But United Airlines’ implementation stands out for its flexibility — especially if you know how to look beyond its app’s SDC suggestions.

Today we’ll go through the ins and outs of what to expect the next time you need to make a last-minute adjustment to your United reservation.

In This Post

General Rules

United’s documentation is breathtakingly short by airfare-rule standards. The key parts:

  • The flights of you and everybody else on the reservation must be on a domestic or international United ticket (with a number starting “016”) and solely on United or United Express aircraft (although on my last international flight, United’s app offered alternate UA-metal flights to get me to the same connection to a Brussels Airlines flight).
  • That includes award tickets, but not Basic Economy fares or certain bulk, group and consolidator tickets.
  • You can SDC starting 24 hours before your scheduled departure.
  • You must pay the fare difference if your original fare class isn’t available. MileagePlus general members and Premier Silver elites also owe a $75 fee, but SDCs are free to Premier Gold, Platinum, 1K and Global Services elites — making this a non-trivial advantage of even mid-tier United status.
  • Origin and destination airports must remain the same, but you can add or remove a connection.

Those rules already grant more choices than American (which yokes you to the original routing) and Delta (which doesn’t let you drop a connection and limits SDCs to flights within the U.S., Puerto Rico, the U.S. Virgin Islands and Canada). United also allows you to keep your confirmed upgrade if you’ve already received one on your original flight, another big boost over its competitors’ policies.

What United’s site doesn’t spell out — but which a FlyerTalk wiki does — is that you can usually avoid eating a fare difference. UA opens up many previously-closed fare classes by the time the SDC countdown starts, and if you wait until a few hours prior to departure, even the cheapest fare buckets often reappear.

Searching for Availability

(Photo by Jason Leung via Unsplash)
Finding an available United flight for SDC is relatively simple. (Photo by Jason Leung via Unsplash)

United’s app will usually offer SDC options when you check in under a “Switch to another flight?” banner. That will reveal alternate routings departing in the next 24 hours, with links to their seat maps and flight status that suggest your upgrade odds. This works after check-in, too; tap the “Trip Details” button on the home-page frame for your flight.

You can run the same search at United’s desktop site (click the “Change flight” link on the reservation page), but the interface is uglier and often incorrectly shows change fees. You also may find fewer results during online check-in, so if you’re going to use your computer, I’d suggest going into manage your reservation.

Finally, you’re also able to explore SDC possibilities at a check-in kiosk, but please don’t if you’ll make other travelers wait.

You can standby for a flight through the app and site, but you shouldn’t have to — because they often don’t capture the full cloud of SDC probabilities. Instead, consult United’s info-dense flight-status reports: Punch in your departure and arrival cities, then check seat maps and standby lists on each flight listed to find routings that should be available.

If you want to take it one step further, familiarize yourself with United’s fare classes. While it may feel like you need a PhD. to do so, it’ll come in handy when you’re trying to utilize the carrier’s SDC benefit. By enabling Expert Mode on United’s website, you should be able to see if your originally-ticketed fare class is available. If that flight option isn’t offered in the app or online, you can be armed with that information when you call to request a change (see below).

Remember also that the 24-hour SDC time frame moves: If you want to stay an extra night somewhere, wait until that bracket shifts to include the next morning’s flights. But time can be your enemy too: UA flights routinely fill up in the closing hours, helping contribute to a load factor that hit 85.4% for domestic flights in 2018.

How to Request a Same Day Change

United's Checkin desk at New York JFK in February 2015. (Photo by Chris Sloan)
Requesting a SDC at check-in is likely the least efficient and least effective method. (Photo by Chris Sloan)

If United’s app or site doesn’t offer your preferred routing, call its reservations line, tell the representative that you want to make a same-day change, and provide the flights you picked out when checking flights for your departure and arrival cities. If the agent says they can’t make that work, thank them for their time, then hang up and call again.

If the representative says you’ll owe a fare difference, thank them for their time, then hang up and call again in a few hours. Be aware that may not work on popular routes like EWR-SFO nonstops, unless you’re okay with a middle seat; on the other hand, last year I cleared a short-haul SDC for my family and I about two hours before our original departure on Sunday of Thanksgiving weekend.

You can also try United’s Twitter account; you’d send your flight info in a direct message, and you’d best do so while you still have at least an hour before your flight.

Finally, FlyerTalk and other reports suggest that requesting an SDC from a check-in counter agent is your least successful and slowest option, so I’d use this as a last resort.

Useful Scenarios

The traditional use case for making a same-day change involves a meeting wrapping up early and a desire to get home to your friends or family. It’s also a nice security policy if a meeting runs late or you get stuck in traffic en route to the airport. However, mastering this opens up helpful possibilities beyond simply getting an earlier or later flight.

  • On city pairs with multiple daily flights (think DCA-ORD) you can book a cheaper flight at a non-ideal time, then take your chances on SDC-ing to the flight you really wanted.
  • You can change to an aircraft with more legroom or better upgrade odds — from a cramped Embraer 145 regional jet to an Embraer 175 with Economy Plus seats and a first-class cabin, or from a 737 to a 767 offering lie-flat seats up front and seatback video throughout.
  • You can drop a connection to save time — or add one to stretch your elite-qualifying mileage.
  • You can change your day’s second flight while on your first flight–for example, if a westbound transatlantic flight will get into Newark or Dulles enough ahead of schedule for you to grab an earlier domestic connection.

Finally, since you can SDC from a flight for which you’ve already SDCed, you could theoretically repeat the exercise over multiple days. But we don’t advise making this a daily habit.

Bottom Line

United’s same-day change policy contains a number of quirks that makes it unique among the major US legacy carriers, but it’s worthwhile to learn them. While the SDC fee is waived for mid-tier (and higher) United elite flyers, there are many instances where it’s worth incurring $75 and adjusting your trip within 24 hours of departure.

Featured photo by Zach Honig/The Points Guy

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