Last chance to catch Full Gallop, a one-woman show about fashion editor Diana Vreeland, wrapping up its first mounting outside New York as opener of the 1997-98 season at Philadelphia Theatre Company. The show began Oct. 31 and runs to Nov. 30 at the Plays & Players Theatre on Delancey Street.

Off-Broadway at Manhattan Theatre Club's Second Stage and then, in a commercial run, at the Westside Theatre, Gallop starred Mary Louise Wilson. In Philly, the play was scheduled to feature veteran actress Nancy Marchand, best known for winning four Emmy Awards as Edward Asner's boss, Mrs. Pynchon, on TV's "Lou Grant." However, due to an undisclosed illness, Marchand has stepped out of the role, with standby Carole Monferdini taking over.

Marchand's last major role was Lady Bracknell in Tony Walton's recent staging of The Importance Of Being Earnest at NY's Irish Repertory Theatre. Her performance was critically acclaimed, though several writers pointed out her occasional difficulty remembering lines. She was nominated for a Tony for her work in the Roundabout Theatre's 1993 mounting of White Liars & Black Comedy. Other credits include The Cocktail Hour, The Octette Bridge Club, Morning's At Seven and Forty Carats.

Monferdini has previously stepped into the Vreeland role both Off Broadway and at the Williamstown Theatre Festival. An OBIE-winner for her work in Circle In The Square's The Club (directed by Tommy Tune), Monferdini also appeared Off-Broadway in Vampire Lesbians Of Sodom and The Foursome. She also toured with Anne Jackson and Eli Wallach in Waltz Of The Toreadors.

* Mark Hampton and actress Wilson penned Full Gallop, which was directed Off-Broadway by Nicholas Martin and his here helmed by Martin and Ira Mont. Wilson received an Obie and Drama Desk Award for her performance as Vreeland in the show's first run, in fall 1995.

Full Gallop catches Vreeland at a turning point in her career. After helping define style from the 40's through the 60's at Harper's Bazaar and Vogue magazines, Vreeland was fired from her position as editor-in-chief of Vogue in 1971. The comedy shows the scattered but vital fashion doyenne remembering past triumphs and deciding what to do next.

Also set for the Philadelphia Theatre Company season are Tom Donaghy's dysfunctional family drama Minutes From The Blue Route (Jan. 16 Feb. 15, 1998); David Rabe's euthanasia drama, A Question Of Mercy (March 27-April 26, 1998) and Birdy, Naomi Wallace's adaptation of William Wharton's novel.

For tickets ($22-$34; subscriptions $60-$114) and information on Full Gallop and other shows at PTC, call (215) 568-1920.

-- By David Lefkowitz