The ballroom design featured 50-foot ceilings, arched windows on three sides and skylights. It included elevated terraced walkways wrapping on two sides of the building, and a main visitors’ entrance on the east.

An enclosed passageway above the east colonnade connected the White House residence to the ballroom on the second floor.

Though the design proposed by McCrery Architects would have dwarfed the rest of the White House complex, Mr. Trump wanted to go even bigger.

Mr. Trump’s vision is to build a ballroom more than twice as large as the one shown here in the proposal by McCrery Architects.

Mr. Trump has said that the ballroom — which is expected to cost $300 million — would not be paid for by taxpayers. He said that he has already raised $350 million from donors, including from major tech and crypto companies.

Davis R. Ingle, a White House spokesman, said in a statement that Shalom Baranes Associates, which is based in Washington, D.C., would join “a team of experts to carry out President Trump’s vision on building what will be the greatest addition to the White House since the Oval Office.”

A White House official said that McCrery Architects would continue to serve as a “valuable consultant” on the project.

Demolition of the White House East Wing underway in October. Doug Mills/The New York Times