News cynosure Walter Cronkite said Monday he would have fired Dan Rather for walking off the set of a CBS newscast and forcing the network to go blank for six minutes. "There's no excuse for it," Cronkite told the University of Texas' student newspaper, the Daily Texan, in Austin. But later, when queried by Associated Press, he softened: "I don't know what I would have done. . . . I would have put a lot of other things into the mix before I would have taken that drastic action." Cronkite, a member of CBS' board of directors, previously refused to comment on the unusual Sept. 11 incident when Rather left his anchor's desk as CBS aired the end of a tennis match instead of switching to the "CBS Evening News" as scheduled. When the match ended and the network quickly switched to the news, Rather was nowhere to be seen.