On Friday night, David Letterman plans to air a six-minute comedy routine that was yanked from his television show in 1993, the Washington Post reported today (Thursday). The routine features Bill Hicks, who died of pancreatic cancer six months after Letterman declined to air it. Hicks's mother, Mary Hicks, will be the first guest on the show. The Post said that neither CBS nor Letterman's Worldwide Pants company had disclosed why Letterman had decided finally to air the routine and that the reason will not be revealed on the show itself.