Original sentence: The sessions were interrupted because many of the musicians on Straight Up left for New York City to participate in the Concert For Bangladesh, organized by George Harrison and Ravi Shankar, at which Russell performed a  medley of the songs "Jumpin' Jack Flash" and "Young Blood"
Edited sentence: The sessions were interrupted because many of the musicians on Straight Up left for New York City to participate in the Concert For Bangladesh, organized by George Harrison and Ravi Shankar, at which Russell performed a  medley of the songs, "Jumpin' Jack Flash" and "Young Blood," and sang a verse one George Harrison's "Beware of Darkness