Now ( I only recently met her) I know a flute player who changes the headpiece on the flute, thus the mouthpiece, but she said such depends on the song she is about to play. I did note that she has 4 different headpieces and the mouthpiece opening was 4 different diameters. She also changes the foot for the same reason and I do believe this changes the key of the instrument, only because the normal foot is called a C foot, She also is wicked on a piano, and plays a piece that trancends styles and genres from the rennnaissance to honky tonk. Once heard a demo in HS from a trumpeter that did a similar trick. For some burst of my what was in my mind , I thought a piano was specially tuned for it to be able to be played in honky tonk. Still puzzling on how to work brass into the blue grass genre. Thanks, I'll stick to playing a colonial fife instead of a flute or piccolo.