Ditmas Management, which is headed by Aaron Sirulnick, and Samson Management are converting the red-brick, 9-story building 40 West 55th Street to a residential condominium.

The property was acquired recently by Ditmas from Macklowe Properties, which had bought it in 1997 from Emigrant Savings Bank for less than $9 million, and renovated it.

The building was built in 1924 and designed by Rosario Candela, an architect best known for luxury apartment buildings on Fifth and Park Avenues.

The renovation by the Macklowe organization created 35 two-bedroom apartments and 1 one-bedroom unit. The apartments have 9-foot-high ceilings, entry galleries, separate service entrances, windowed kitchens and baths, and fireplaces and half of the apartments have formal dining rooms.

The building is adjacent to the famous Rockefeller Apartments at 24 West 55th Street, a building that extends through to 54th Street and which is notable for its large curved living rooms with large windows and center garden.

This building, which has a concierge and a curved lobby, was originally an apartment house, and for several decades was used mostly for offices and showrooms, and, for a while, as the headquarters for Ralph Lauren, and then, more recently as furnished rental apartments.

Samson Management's other projects in Manhattan have included 50 Madison Avenue and 120 Liberty Street.

The building has a one-story limestone base with a broken pediment entrance surround and wall lanterns, handsome window surrounds on the second floor with lunette tops with escutcheons and rope quoins and window surrounds on the top floor with rope quoins beneath handsome decorative garlands and swags.

The building has discrete air-conditioners that break into stringcourses above the third and sixth floors and into the window surrounds on the second floor.

The building is across from the Shoreham Hotel.