One sure sign that winter has not yet loosened its grip is a cancellation notice posted outside a concert hall. Such a message greeted people as they arrived last night at the Kennedy Center, where pianist Murray Perahia had been scheduled to appear before the flu caught up with him. The Washington Performing Arts Society found a willing substitute in Ann Schein, who made the most of the assignment by performing the kind of all-Chopin recital that has been earning her attention lately in New York.

Schein's playing was marked by a gracefulness, a certain restrained style that would have been more ideally suited to an intimate salon, and yet she managed to convey enough of the power in Chopin's music to keep the program from sagging. If her interpretation of the 24 Preludes lacked some of the intensity that other pianists have discovered in them, her way with a phrase was often delectable, especially in the familiar E minor and A major passages.

A tendency toward blurring whenever the pace quickened took its toll here and there, but Schein's basically sensitive and secure technique carried her admirably through the concluding collection of Etudes, Impromptus and the B minor Scherzo.