Jennifer Harmon , a prolific Broadway performer who often understudied more widely known actors such as Stockard Channing, Judi Dench, Jessica Lange and Jessica Lange, and who appeared as a regular on the ABC soap One Life To Live in the 1970s, died Saturday, May 9. She was 82. Her death was announced by family. No cause was stated. A resident of New York, Harmon, born December 3, 1943, was cast in 21 Broadway productions, from her debut in 1965’s You Can’t Take It With You to 2011’s Other Desert Cities . In the latter, she was an understudy for Channing before later taking over as a replacement. Among her other Broadway credits were The School for Scandal (in both 1966 and a revival in 1995), Blithe Spirit (1987); The Sisters Rosensweig (1993); The Little Foxes (1997); The Deep Blue Sea (1998); Amy’s View (1999); The Glass Menagerie (2005); and Edward Albee’s Seascape (2005). She was an understudy in two Neil Simon Broadway comedies: The Dinner Party (2000) and Barefoot in the Park (2006).…