Hill & Knowlton, New York, named Eric Borsum and Alan Elias senior managing directors; they will jointly manage the Los Angeles office's corporate services group. Mr. Elias will continue directing the office's media relations and media training activities. Mr. Borsum, a strategic counselor, will continue to handle several accounts. They replace Greg Waskul, who will remain a consultant but pursue other ventures.Joanne Zaiac, 35, to director-client services at Wunderman Cato Johnson, New York, from exec VP. She also becomes account managing director of Young & Rubicam's American Express Worldwide business.Peter Fisher is promoted to New York advertising manager, Men's Journal, a new position, from category development manager. Also, Rich Antoniello to New England account manager, replacing Jill Seifert, who left..