Southwest Airlines is now limiting a service that lets passengers buy a better spot in the boarding line

. The airline announced that its Boarding Preferred program will only be available to passengers who hold one of its most expensive fares, called Anytime. The previous version of the service allowed customers on the “wanna get away” tickets to also pay extra for a better boarding spot. Anytime tickets, which cost more than twice as much as the “wanna get away” fares, allow customers to fly on any southwest flight. Southwest said passengers who paid to use the boarding preferred program under the old rules will receive a pro-rated refund, and that it is updating its website to reflect the changes.