Complex sentence: When KASW switches to The CW, it will be the largest affiliate to not be owned by CBS Corporation or Tribune Broadcasting, as it is owned by Belo Corporation in a duopoly with KTVK.
Split into simpler sentences: When KASW switches to The CW, it will be the largest affiliate not owned by CBS Corporation or Tribune Broadcasting. KASW is owned by Belo Corporation, in a duopoly with KTVK.