Southwest Airlines quietly walked back its January policy shift.

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Southwest Airlines is rethinking a policy that upset some travelers earlier this year.Last week, the airline quietly updated its "customer of size" policy for passengers who may need an extra seat."On flights where adjacent seats are available, our Agents at the airport are empowered to provide an additional seat at no extra cost to Customers who require one," a spokesperson told Business Insider.The change comes after Southwest faced backlash over a policy change that went into effect on January 27. The rule said passengers who needed an extra seat would be required to purchase one before boarding the flight. The decision on whether a passenger needed an additional seat was left up to Southwest's discretion. The policy shift was part of a wave of changes at Southwest, including the introduction of assigned seating.While Southwest doesn't list size requirements for passengers, it lists the dimensions of its seats in its policy. According to the guidelines, the armrests on the seat are the boundary markers between seats.The airline came under fire on social media for the January policy, as some travelers complained about being charged a "fat tax" for flying Southwest. Others took issue with the way it was implemented, with gate agents publicly calling out plus-size flyers in some instances.Before the change, Southwest's rules for plus-size passengers were considered among the best in the industry. The airline typically offered passengers free accommodations.