This season's final cast change in the Washington Opera's production of "The Rake's Progress" is a smashing success for soprano Susan Peterson. Sheri Greenawald, who opened the season in the role of Anne Trulove, has now gone off to sing it in Europe.

No loss of quality could be detected last night in the singing, acting or ensemble work as a result of this change. The production, now running with substitutes in both of its romantic leads, is completely smooth, and Peterson may even have a small edge on her predecessor in the clarity of her diction and the warmth she brings to the role.

Those who recall her work with this company in "Monsieur Choufleuri" and "Trial by Jury" know that she is a talented singer and actress -- but neither of those comic roles makes the kinds of demands Stravinsky imposed on his heroine. Vocally, she has two of the opera's biggest (though not especially spectacular) solos as well as quite a bit of ensemble singing, and she was equally impressive when working with partners and when she was alone on the stage.

Theatrically, she has to be convincing as a nice country girl in a world of prostitutes, social climbers and madmen, where her successful rival is a bearded woman. Like Micaela in "Carmen," she must make goodness seem interesting in competition with vividly colorful evil. Her projection was a bit weak in the first scene, but by the opera's end she emerged as a three-dimensional, thoroughly believable person, even amid the frenzy of the auction scene and the opera's harrowing conclusion in a madhouse. She will repeat the performance Saturday night when this production ends its run.