Larry A. Kohn will assume joint oversight of J.P. Morgan Alternative Asset Management with CIO Peter Zumo. The two will replace President and CEO Joel Katzman when he retires April 30, Mr. Katzman said.Mr. Kohn joined the hedge funds-of-funds manager Feb. 28 and will handle the administrative and operations side as head of business management. It is a new position. He was managing director and an institutional marketer at hedge funds-of-funds manager Quellos Group, which he left last June. JPAAM manages nearly $9 billion in hedge funds-of-funds strategies.