Talk about a hardact to follow. Kathleen Chalfant won an OBIE, a Lortel Award, a Drama Desk Award and Outer Critics Circle Awards for her role in Margaret Edson's Pulitzer winning drama, Wit. But all great things come to an end, and Chalfant left the role Aug. 8 (though she'll play Vivian Bearing once more, Jan. 18-Feb. 20, 2000, when Wit comes to Los Angeles' Geffen Playhouse).

Judith Light, best known for her eight years on ABC-TV's "Who's The Boss," took over the role in New York back on Aug. 10, but Sept. 9 is the show's official "re-opening" date. Also added to the cast when Light came onboard were William Cain (The Heiress), Sally Parrish (The English Teachers) and Grant Show ("Melrose Place") in the roles of Dr. Harvey Kelekian, Dr. E.M. Ashford and Dr. Jason Posner, respectively.

Light's stage credits include playing the maid in a 1975 Broadway mounting of Ibsen's A Doll's House (opposite Liv Ullman and Sam Waterston), as well as the Broadway play Herzl.

Wit, playing at the Union Square Theatre, tells of a strict college poetry professor brought low -- to humility and humanity -- by her bout with ovarian cancer. A national tour of the show is planned for January-September 2000, but no casting has been announced.

For tickets and information on Wit, directed by Derek Anson Jones, call (212) 307-4100. -- By David Lefkowitz