sentences:  O'Sullivan's resignation allowed the administration the opportunity to reorganize.The position was offered to three retired generals, John J. Sheehan, Jack Keane, and Joseph Ralston, before the appointment of Lieutenant General Douglas Lute in May 2007; Lute was confirmed by the Senate on June 28, 2007, and reported both to the President and the National Security Advisor with the rank of full "Assistant to the President.