The director of the CIA’s National Clandestine Service, the storied home of the agency’s most secretive intelligence operations, has announced that he plans to retire, The Daily Beast has learned.

CIA spokesman Dean Boyd confirmed that the director announced his retirement “after a long and distinguished career at CIA. We thank him for this profound and lasting contributions to both CIA and to our nation’s security.”

As a practice, the CIA doesn’t identify the head of the clandestine service by name. But Frank Archibald was outed in a Twitter post in 2013, and details of his biography were known to some journalists. Archibald, who was 57 when he took the job that year, reportedly served tours in Pakistan and Africa and also headed the CIA’s Latin America division. The Associated Press reported that Archibald "once ran the covert action that helped remove Serbian President Slobodan Milosevic from power."

Archibald’s retirement comes at a transitional moment for the CIA. The agency’s director, John Brennan, is considering major changes to the agency’s structure, including the possible creation of new intelligence centers and doing away with the traditional division of CIA into its analysis group and the clandestine service.

Critics of the reorganization, which hasn’t been formally proposed and, officials have stressed, isn’t a done deal, see it as potentially undermining some of the CIA’s core capabilities in favor of organizing the agency around regions of the world. Some in the National Clandestine Service in particular view a reorganization as a threat to the high-degree of independence it has traditionally enjoyed within the intelligence bureaucracy.

“This would be to their mind the greatest threat to their independence since they were created as the Directorate of Plans back in 1951,” one former official said.

Brennan is slated to make public remarks on Monday at the Council on Foreign Relations in New York, where he’ll be interviewed by journalist Charlie Rose. The CIA hasn’t announced what, if any, news Brennan plans to make. But former officials said they’d been anticipating that he might soon unveil more of his thinking about any reorganization.

The CIA has also seen some shakeups in the senior ranks of late. Earlier this month, President Obama tapped David Cohen to be the CIA’s new deputy director. Cohen, a senior Treasury Department official, has been the chief architect of the administration’s sanctions regime against Iran.

Also this month, Lt. Gen. John F. Mulholland Jr., who previously was deputy commander of U.S. Special Operations Command, became the CIA’s new associate director for military affairs. In recent years, the CIA and special operators have worked more closely together than ever, most famously in the successful raid that killed Osama bin Laden in Pakistan 2011.