Goodby Silverstein & Partners will no longer handle Constellation Brands' Corona Light and Modelo Especial. The Chicago-based beer importer is actively searching for a new agency for the two brands. The agency and marketer both said that the two parties mutually agreed to end their relationship. Corona Light hasn't gotten the same exposure as Corona Extra, which is handled by Chicago ad agency Cramer Krasselt. Goodby launched a campaign aimed at middle-age drinkers.