Complex sentence: He subsequently lost the post of Music Director, though he would occasionally conduct the Philharmonic after that, even leading some important concerts such as the orchestra's premiere performance of Stravinsky's "Symphony in Three Movements" in 1946.
Split into simpler sentences: He subsequently lost the post of Music Director, though he would occasionally conduct the Philharmonic. He lead some important concerts, such as the orchestra's premiere performance of Stravinsky's "Symphony in Three Movements" in 1946.