Phyllis Henderson (Dorthea) Past Centre Stage roles: 9 to 5 (Margaret), ‘Night, Mother, (Thelma Cates). Other favorite roles: Bright Star, (Mama Murphy) (MTP), Sound of Music (Mother Superior) (GLT). Phyllis is excited to be (finally) performing this play live at Centre Stage! Today I am going to prove that man can fly without the aid of any motor of any kind.