Westwood One Inc., the No. 1 U.S. distributor of radio programming, said that CBS Radio extended a management agreement and that Joel Hollander will replace President and Chief Executive Mel Karmazin. Hollander is now vice president and general manager of CBS' WFAN in New York, the top U.S. station in terms of revenue. Karmazin also is CBS president and chief operating officer. Culver City-based Westwood One manages the sales, marketing and administration of the CBS Radio network.