The City Council is expected to hold a hearing on the deal in early May, said Councilman Ben Kallos, who chairs the committee on governmental operations, which includes oversight of the Department of Citywide Administrative Services.

Former senior officials who worked in previous administrations said the powers of the department had grown over the years. It was formed in 1968 under former Mayor John Lindsay as the Municipal Services Agency.

In the 1990s, under Mayor Rudy Giuliani, the agency merged with the Department of Personnel. It now commands an annual budget of $1.2 billion and employs 2,000 people.

The former officials said the department should have flagged the Rivington House deed modification to the mayor’s Office of Contract Services and the Law Department. A lawyer for the mayor signed the deed modification, but Mr. de Blasio said he wasn’t aware the lawyer signed iCityt.