Rick and Kathy Hilton got to visit their daughter Paris yesterday at the Twin Towers Correctional Facility — Sundays and Tuesdays are the days when prisoners are allowed to see family and friends. Like her previous visitors, sister Nicky and ex Stavros Niarchos, Paris' parents were whisked past the waiting line of people — causing plenty of grumbling among the other prisoners' visitors who had to wait for hours. Kathy told reporters outside the jail that Paris "really hasn't had much sleep." And in news of people not standing by Paris, her talent agency, Endeavor, has announced that the reality-show star has been dropped. "She is no longer a client," said Michael Donkis, a spokesman for the company.