that the existing steel frame increased construction costs by 25 percent, but it also allowed him to include more usable space than a completely new building on the site. The two ends of the Biltmore's "U"-shaped massing were connected, turning the hotel into an "O"-shape. A new elevator core was built and a 28-story atrium was created in the center of the building. The facade was also rebuilt with brown granite, and elevators, heating, cooling, and other mechanical systems were entirely replaced. The lowest three stories were converted into of retail space. The Palm Court's clock was the only decoration from the hotel that was preserved. The Metropolitan Transportation Authority owned the driveway on 44th Street and the Biltmore Room in the basement, and a Catholic bookstore occupied a storefront at 43rd Street and Vanderbilt Avenue; these three spaces remained intact. The hotel's redevelopment was temporarily halted in April 1982 after leaks developed in the Biltmore Room. Milstein subsequently paid for a restoration of the Biltmore Room, which reopened in April 1985 following a renovation designed by Giorgio Cavaglieri. Office use Bank of America had started moving into the 2nd through 14th floors of the structure by late 1983, and the former Biltmore reopened on May 15, 1984, as Bank of America Plaza. Initially, Bank of America only occupied half of the 28-story building. Other tenants included telephone company NYNEX on the 20th and 21st floors; real-estate services firm Landauer Associates on the 18th floor; and the Union Bank of Bavaria and Westpac on one floor each. When Bank of America Plaza opened, several other large banks were relocating to Madison Avenue. Paul Goldberger criticized the new design, saying, "Now the East Coast headquarters of the Bank of America, this is a bloated, heavy form of glass and polished granite, unrelieved by any of the gracious ornament that made the old Biltmore so beloved a presence." The structure also became known by its address, 335 Madison Avenue. Further tenants moved into the building in the 1990s, such as the American Management Association and the New York Life Insurance Company. By the 2010s, the building's tenants included several technology companies, such as Addepar and Facebook Inc.. During that decade, city government officials sought to change zoning regulations around Grand Central Terminal as part of the Midtown East rezoning plan. After the Midtown East rezoning was announced, Paul Milstein's son Howard Milstein