Federal Reserve (Fed) Vice Chairman Donald Kohn, a 40-year veteran of the U.S. Central Bank, will leave in late June, giving President Barack Obama a chance to reshape the institution. In a letter to Obama released Monday, Kohn, who has served as the Fed's Deputy Chief since mid-2006, said he will leave when his current term expires on June 23. “The Federal Reserve and the country owe a tremendous debt of gratitude to Don Kohn for his invaluable contributions over 40 years of public service,” Fed Chairman Ben Bernanke said in a statement.