Booking travel by air can be a daunting process, as potential passengers shop around for the most inexpensive airfare possible that suits their needs.

But Southwest Airlines  (LUV)  has one feature for purchasing tickets designed to make the task easier.

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As most travelers know, airfare fluctuates in price from day to day and also according to the number of days between booking flights and the travel dates themselves.

Those buying tickets are left to search online or on carrier apps for the best combination of dates, including the timing of when to make purchases, to get the best deals.

It may sound too good to be true, but Southwest Airlines has what turns out to be a lucrative alternative to all this work that more people will undoubtedly want to know about.

Southwest offers a major feature that saves passengers money

The fact is, if you book a flight on Southwest and it becomes less expensive after your purchase, you can rebook it at any time right up until very shortly before it leaves.

“Booking a flight can feel like a gamble,” wrote a team of authors for The Points Guy. “You never know what the price might be a few days or months down the line, and it’s hard to know if you’re booking the lowest possible rate. Should you book now? Hold off a few days? A few months? It can be a stressful process, especially when buying tickets for an entire family.”

“But not with Southwest Airlines. One of the longstanding perks of this airline is that with a push of a few buttons, you can rebook any reservation,” continued the authors. “If the price has decreased, you’ll get the difference back. There’s no fee to do this, and the airline even allows you to go through this process an unlimited number of times up to 10 minutes before the flight’s departure.”

The only trick to making this happen is that passengers should re-check their flights on several occasions after booking to see if the airfare price has fallen.

The chance of this happening is increased by booking months before traveling. More days between booking and flying provide more opportunities to see price reductions.

The two ways the process works

If the price of your flight goes down, you can receive either a Travel Funds credit or points back, depending on how the ticket was originally purchased.

If you paid for the flight, you will get the Travel Funds credit for the difference in the fare.

“Fortunately, these credits no longer expire and will stay in your Southwest account until you redeem them,” The Points Guy wrote. “Travel Funds credits from these fares are nontransferable and can only be used for the same passenger.”

If you used points for the flight, the difference in Rapid Rewards points will be moved into the account from which you had originally deducted them.

Here is the process for taking advantage of this program, according to The Points Guy.

First, sign in to your Southwest Rapid Rewards account. On the “My Account” page, you’ll see all of your upcoming flights. Find your flight and click on “Change flight.”

Your original departure and arrival airports, as well as the date, will automatically populate. Click “Explore options.”

You’ll see the amount that each flight has decreased (or increased) in points or cash. If your original flight has decreased (noted by a minus sign), select the fare to get a credit. This is the exact same process you’ll follow if you want to change your flight to a completely different flight.

Then, click “Review changes.”

You will see the credit you are receiving at the bottom of the page. If you want to continue, click “Review Passenger and pricing.”

The passenger information will already be populated on the next page, and you’ll just need to confirm your changes.

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