Moody’s Investors Service lowered the subordinated debt rating of Capital Cities Communications to A2 from AA3 and reduced the senior debt rating of American Broadcasting Cos. to A1 from AA3 . . . Levi Strauss & Co.'s board of directors approved a previously reported $50-per-share cash buy-out proposal made by descendants of the company’s founder . . . Federal Express said the FCC approved its plan to build a domestic satellite communications network to support the firm’s package delivery and Zapmail services . . . United Press International and the union that represents its employees agreed to let a mediator help resolve their dispute over wage and benefit concessions.