It was last call at Elaine’s, and it packed the house. “Half the people in this room are never going to see one another again,” writer Gay Talese said last night. “This is saying goodbye to one another.” Also there was former NYPD Commissioner Bill Bratton, who predicted, “You’re going to hear the term ‘bittersweet’ a lot to night.” Bratton’s wife, broadcaster Rikki Klieman, said, “I don’t know what many of us will do. I guess we’ll just have to stay home.” Among other celebrities who came to say farewell were Alec Baldwin and former Gov. David Paterson. The Upper East Side restaurant, famous for attracting A-listers, couldn’t hang on after the death of its legendary owner, Elaine Kaufman. The Post’s Jennifer Gould Keil learned, however, that the place may be reborn under the name of another famous restaurateur. The owners of P.J. Clarke’s are negotiating to buy Elaine’s and reopen it as part of their chain.