United Airlines warns of a planned system outage — what to know ahead of your flight

The update is a modernization of United’s flight reservation system

During the upgrade, United passengers won't be able to manage their bookings online (Getty Images)

United Airlines is conducting a planned overnight technology upgrade affecting its flight reservation system on Wednesday, February 4, between 1.30am and 5am CST (2.30am and 6am EST/11.30pm February 3 to 3am February 4 PST).

As a result, many of its web and app services will not be available during that time, including for United employees.

Passengers can book, complete check-in, or make trip changes prior to 1.30am CST (2.30am EST/11.30pm February 3 PST) on February 4 or when the upgrade is complete, United said.

What won’t be available during the update is the ability for passengers to go online and cancel flights, book new flights or check-in, make seat selections or upgrades, or view or retrieve boarding passes in the app.

However, flights will operate as normal and passengers will be able to check in at airports, though they should be prepared for longer waits at counters.

United Airlines is conducting a planned overnight technology upgrade affecting its flight reservation system on Wednesday, February 4, between 1.30am and 5am CST (Getty Images)

To help alleviate delays, passengers are advised to amend bookings, and download or screenshot boarding passes or print paper copies, ahead of the maintenance window opening.

The upgrade will shift the “brains” of United’s booking system, called Shares, from an older data center in North Carolina to a newer hub in Chicago.

The aim of the move is to improve reliability.

To help alleviate delays, passengers are advised to download or screenshot boarding passes or print paper copies ahead of the maintenance window opening (Getty Images)

United, the largest U.S. airline by fleet size, with 1,000 aircraft, has been warning passengers about the outage and reportedly adjusted domestic schedules to keep operations running as smoothly as possible.

Scott Keyes, founder and CEO of flight deals website Going.com, told CBS News: “Don’t freak out if you can’t search for flights in the middle of the night.”

“It will come back online soon.”