Let’s be honest. When most of us book a flight, the last thing we think about is the message that appears after our confirmation about our right to a full refund under the 24-hour flight booking rule.

This is typical. Chances are, you found a cheap flight, or you’ve done enough research that you are happy with the prices that have come across your screen.

But there are times when the inevitable happens. You realize the dates are off. The hotel prices you want are higher than you wanted to pay, and changing the dates by even a day would fit your budget. There are even times when a price alert comes to your phone for the same route, but at a slightly lower price. Your stomach drops.

Here’s what many travelers often lose sight of: you have a full 24 hours to undo your reservation, completely free of charge. You can thank the U.S. Department of Transportation for this. Federal regulation requires airlines to allow passengers to cancel or change a booking without penalty for 24 hours. The refund is issued back to the original form of payment. It doesn’t come with any caveats, such as flight credits or added fees.

While airlines won’t advertise this regulation loudly, it is an underused consumer protection that can serve as a safety net for mistakes and as a strategy for locking in fares. The benefit works regardless of fare class, including Basic Economy, business class, or a deeply discounted sale fare. The airline cannot force you to accept a voucher or travel credit.

Here’s how to use the 24-hour flight booking rule to your advantage.

Who It Applies To (and Who It Doesn’t)

The 24-hour rule allows free cancellations or changes for flights booked directly with the airline. The rule applies to flights at least 7 days before departure and to those that originate in or fly to the U.S., including foreign carriers.

Travelers who use online travel agencies (OTAs) will not have access to the 24-hour rule, so it’s best to go directly through the airline. While most U.S. airlines follow the U.S. Department of Transportation’s rule, international airlines and OTAs have different policies. Many airlines offer a free 24-hour price hold instead of a free 24-hour cancellation.

How To Make The 24-Hour Rule Work For You

That Date Mistake? You Can Still Fix It

Mistakes are more common than you think when you are excited about a flight deal. Review your name, date of birth, Known Traveler Number (KTN) for TSA PreCheck, and even the route before you purchase the flight.

If you still make a mistake, don’t worry. Use the 24-hour window to correct these mistakes with no penalties or fees. Remember to take a screenshot of the booking confirmation, including timestamps, to mitigate any confusion or disruptions when canceling the flight within the 24-hour window.

Lock In A Fare Without Committing

One common mistake when booking a flight is assuming prices will go down. Sometimes, the price you see is the best option, especially when using the tools and resources to monitor flight prices.

One strategic way to use the 24-hour window cancellation rule to your advantage is with the “book now, think later” approach. This is especially beneficial with flash sales and mistake fares that come up.

Google Flights and Skyscanner are great platforms for spotting fares, booking directly with airlines, and getting real-time data on whether flight prices are typical, above average, or below average. If the prices are average or below, then book the flight. Use the next 24 hours to confirm PTO dates, check hotels, and get your travel buddy on board.

Monitor For Price Drops After Booking

The saying “the grass isn’t always greener on the other side” is actually not true with airfare. Prices fluctuate multiple times throughout the day, so don’t treat your recently booked flight as the end-all, be-all. Don’t be afraid to use the cancel-and-rebook strategy during your 24-hour window.

Use tools that monitor prices and alerts to help you track any price decreases throughout the day. If a better fare becomes available, book the new flight before canceling the original. Your 24-hour window on the new booking starts fresh from that moment. But act quickly. Your original booking’s window is still ticking, and you’ll want to cancel it before that clock runs out. Make sure you’re happy with the new route and seats before making any changes to your itinerary.

Keep in mind that after the 24-hour window closes, you will only receive travel credits, and in some cases, a rebooking fee may be applied.

Knowing Your Rights

While it may be true that using the U.S. Department of Transportation’s 24-hour cancellation rule is rare, there are tremendous benefits for travelers. Not only does it provide relief for mistakes, but it’s also a great way to lock in cheaper fares and help you plan when error fare alerts hit your email or phone.

Remember: use the benefit by booking directly on the airline’s website, avoid OTAs, book at least 7 days in advance, set an alarm 23 hours after booking as a reminder, and have your apps ready if you need to cancel.

Always save your cancellation confirmation. The best travel hack isn’t a trick. It’s simply knowing your rights.