Norah O'Donnell's final sign off from "CBS Evening News"

After five years at the helm of "CBS Evening News," Norah O'Donnell is signing off for the final time Thursday as she prepares for a new role with the network. In a special sendoff, Oprah Winfrey looks back at O'Donnell's tenure as anchor and managing editor, from her historic interview with Pope Francis, to her live broadcast aboard the USS Nimitz.