 Flor served as chief conductor of the Konzerthausorchester Berlin from 1984 to 1991.He was artistic advisor and principal guest conductor to the Tonhalle Orchestra Zürich from 1991 to 1996.He was principal guest conductor of the Philharmonia Orchestra from 1991 to 1994, and became principal guest conductor of the Orchestra Sinfonica di Milano Giuseppe Verdi in 2003.