You’ve read all of your free items this month. To register, get added benefits and unlimited access to articles, Become a Member. Already a Member? Sign in. Advertising Age Article Abstract Chevrolet to Begin Review for New Shop Assignments Campbell-Ewald to Remain Lead Agency; Non-Roster Shops Will Be Considered By Jean Halliday, Published on October 15, 2009 12 Want more Access, Content & Connections? Upgrade to Membership. We are glad you are enjoying Advertising Age. To get uninterrupted access and additional benefits, become a member today. Become a Member Already a member? Log in.