Ms. Silverstein and the elder Ms. Beber founded the agency in 1972. Both co-chairwomen will focus on developing new business for the $49 million shop. Clients include John Alden Life Insurance, Coty Fragrances' Tribe brand, Florida Power & Light and El Presidente Hotels in Mexico.
Jennifer Beber, whose former post won't be filled, has been overseeing client services and daily operations for nearly two years.
"It's not like we crossed some line. It just recognizes what's been going on," she said.
Before joining the agency six years ago, Jennifer Beber spent five years in strategic planning with Scali, McCabe, Sloves, New York.