Arthur Cotton Moore, the local architect, author and painter picked by Donald Trump and his daughter Ivanka to design a redevelopment of the Old Post Office Pavilion, has dropped out of the project to take a medical leave of absence, according to his wife and business partner, Patricia Moore.

In an interview, Patricia Moore declined to detail her husband’s health problems, but said he was still working on two books despite having to cut back on his architecture work. “It should be a temporary thing, as far as his pulling back,” she said.

Moore, a sixth-generation Washingtonian who attended St. Albans School, provided the Trump Organization with a local and trusted architectural voice in winning a competition to be named developer of the project by the General Services Administration. Moore’s past projects include the renovation of the Library of Congress, the Washington Harbour complex on the Georgetown waterfront and Canal Square in Georgetown.

The Trumps have named Hany Hassan, partner and director of the D.C. office of Beyer Blinder Belle Architects & Planners, to their team to replace Moore. He has provided design and other services to the GSA, the Smithsonian, the State Department and other organizations with historical buildings in Washington.

Ivanka Trump, who manages the Old Post Office for the Trump Organization, said she was saddened to learn of Moore’s illness, but that her team of architects would build off his work.

“Arthur has been an invaluable member of the team and our plans going forward will continue to honor his great vision for this iconic building,” she said.

Trump said Hassan has “done a ton of preservation work at the Smithsonian and many other historic buildings around the city, so he has tremendous experience and will be a great partner going forward.”

Patricia Moore said her husband, 77, had been working seven days a week on the Old Post Office and other projects, including two books that he is close to publishing. She said she called the Trumps in mid-July to say they needed to step away.

“There are huge feelings between us and the Trumps,” Patricia Moore said. “It’s a really sad event. But there’s all good feelings. We’re here for them and they’re here for us, I’m sure. Life happens.”