Southwest Airlines will soon require travelers who don’t fit within the armrests of their seat to pay for an extra one in advance, part of a string of recent changes the carrier is making.

The new rule goes into effect Jan. 27, the same day Southwest starts assigning seats.

Currently, plus-size passengers can either pay for an extra seat in advance with the option of getting that money back later, or they can request a free extra seat at the airport. Under the carrier’s new policy, a refund is still possible but no longer guaranteed.

Southwest said it is updating some of its policies as it prepares for assigned seating next year.