In 2026, the ability to change a flight within 24 hours of booking in the UK depends on the airline's specific policy, as there is no UK law equivalent to the US "24-hour refund" rule. However, many major carriers like British Airways offer a 24-hour "cooling-off period" where you can cancel or change your flight for a full refund (or for just the fare difference) if the booking was made directly on their website. Low-cost carriers like EasyJet and Ryanair are much stricter; while they may allow name corrections or minor changes for free within a very short window (e.g., 2 hours), they typically charge a change fee plus the fare difference for any destination or date changes made after that. If you are within 24 hours of the actual flight departure, most "Standard" or "Economy" tickets are non-changeable unless you have a "Flexible" fare, which allows for last-minute adjustments, usually for a significant price.