NEW YORK (AP) — JetBlue said Monday that CEO Robin Hayes will step down next month and John Caldwellbe replaced by the airline’s president, Joanna Geraghty, who will be the first woman to lead a major U.S. carrier.

Geraghty, 51, joined JetBlue in 2005 and has taken on an increasingly prominent role at the New York-based airline in recent years, including becoming president and chief operating officer in 2018.

Geraghty said she was honored to get the new job, and said she was looking forward “as we execute on our strategic initiatives, return to profitable growth, and generate sustainable value” for shareholders.

Hayes, 57, said he will retire for health reasons.

“The extraordinary challenges and pressure of this job have taken their toll, and on the advice of my doctor and after talking to my wife, it’s time I put more focus on my health and well-being,” Hayes said in a statement.

The change at the top will occur on Feb. 12. It comes as JetBlue waits for a federal judge in Boston to decide whether it can purchase Spirit Airlines in a bid to grow quickly into a challenger to the biggest U.S. airlines. The Justice Department sued to block the deal, and a trial was held last fall.

Hayes, 57, is a former British Airways executive who joined JetBlue in 2008 and became CEO in 2015. He pushed the airline to start transatlantic flights and create a partnership in the Northeast with American Airlines. The deal with American was disbanded, however, after the Justice Department successfully sued to kill it.

JetBlue is the nation’s sixth-biggest airline by revenue, slightly behind No. 5 Alaska Airlines.