Top executives announced their retirement plans at two Minneapolis shops last week. At Campbell Mithun, chairman Bill Dunlap, 65, said he will step down in June, 22 years after joining the agency as president. He will consult with president and CEO Les Mouser as chairman emeritus. At Carmichael Lynch, Charlie Anderson, 51, retired April 30 as managing partner and chief financial officer. Mark Feriancek, who joined the agency last May, took on his responsibilities May 1.