CNN officially announced Tuesday that John Roberts will leave its morning show, "American Morning," at the end of the year. The network also said that it will be revamping the show and that a series of interim anchors will take Roberts' place alongside Kiran Chetry for the time being. In addition, the show's executive producer has jumped to NBC News.In a memo to staff, CNN president Ken Jautz said that the network is "discussing" an Atlanta-based role for Roberts.