To change your seat after checking in, you should first try the airline's official mobile app or website under the "Manage Booking" or "Check-In" section. Most modern carriers in 2026 allow you to revisit your digital boarding pass and select an "Edit Seat" or "Change Seat" option, provided the flight isn't fully booked. If the app shows the seat map as locked, your next best step is to use an airport kiosk or visit the check-in counter to speak with an agent. For last-minute changes, the gate agent is your ultimate resource; they have the most up-to-date control over the manifest and can often see seats that were released by "no-show" passengers or upgrades. It is important to remember that if you move to a seat with extra legroom or a premium location, you may still be required to pay an additional fee even after the initial check-in. If you are a frequent flyer with elite status, your chances of a successful post-check-in change are significantly higher, as the system often prioritizes your requests during the final boarding preparations.