Starting Jan. 27, Southwest Airlines passengers will get assigned seats for the first time, marking a major shift in the carrier’s business model.

What fare product you choose: As part of the shift, Southwest will rename its fare classes. They'll be called: Basic, Choice, Choice Preferred and Choice Extra (the latter of which will come with an extra legroom seat). Higher-priced fares come with an earlier boarding group.

“Southwest open seating is the ultimate expression of its founding ethos: to make air travel affordable and accessible for everyone.”—Official Southwest Airlines statement, as part of the airline’s 50th anniversary commemoration.