Carolina Herrera has expanded its third floor, just in time for the social and bridal seasons (954 Madison Ave., at 75th St.; 212-249-6552). A winding staircase leads to an airy space with bay windows and striped satin sofas so your glamour squad can wait comfortably while you pick through elegant eveningwear. And Charles Tyrwhitt’s second store, open November 10 (745 Seventh Ave., at 50th St.; 212-764-4697), has a luxury grooming section in addition to the men’s and women’s collections.