After suffering a public relations nightmare when a passenger was dragged off a fully booked flight a week ago, United Airlines said Sunday it is changing policy and will no longer allow crew members to displace customers already aboard a plane.

The change comes after a passenger, Dr. David Dao, was dragged from a fully booked United Express flight at O’Hare Airport after he refused to give up his seat to make room for crew members trying to get to Louisville, Ky., where they had a flight to work.

Cellphone video of the incident sparked widespread outrage aimed at United.

Under the change outlined in an internal email dated Friday, no crew member “can displace a customer who has boarded an aircraft.” And flight crews have to make must-ride bookings at least 60 minutes prior to departure. Previously, they could be booked until the time of departure.

United spokeswoman Maggie Schmerin said Sunday the changes are the first steps in a review of policies and are meant to ensure that situations like Dao’s never happen again.

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Dao suffered a concussion and a broken nose, lost two teeth and needs reconstructive surgery to repair damaged sinuses, his attorney Thomas Demetrio said last week. Demetrio said Dao — who was released from a hospital Wednesday night — is poised to become the poster child of an airline industry gone awry.

Dao has yet to speak publicly on the matter but will when the time is right, said Demetrio, adding that a lawsuit against United is likely.

United CEO Oscar Munoz, after initially defending his employees, issued a more contrite statement and then appeared on ABC-TV and said the video of Dao being dragged off the plane filled him with “shame.”

He promised a full internal review and to release the results by the end of April.

Police officers from the Chicago Department of Aviation took Dao off the plane. Three of them have been placed on leave. Their names haven’t been released.

Contributing: AP