Willem Mengelberg
One of the first occasions after Mahler's death where the conductor reverted to the original movement order is in 1919/1920, after an inquiry in the autumn of 1919 from Willem Mengelberg to Alma Mahler in preparation for the May 1920 Mahler Festival in Amsterdam of the complete symphonies, regarding the order of the inner movements of the Sixth Symphony. In a telegram dated 1 October 1919, Alma responded to Mengelberg: