A 2nd high-ranking exec left Viacom in as many weeks Mon when Betsy Frank left her job as evp, research and planning. Just last week, Nickelodeon pres, Herb Scannell, left after early 2 decades with the company. — Cartoon Network promoted Dawn Lee Williamson to vp, ad sales/marketing. — Harron Comm named Joel Cohen as chmn and James Bruder as pres. The 2 replace longtime chmn/pres Paul Harron, who died in Dec. Bruder is Paul Harron’s nephew. — Sesame Workshop hired Susan Kolar from Oxygen to be evp/CAO. — FSN hired David Leepson as vp, development.