Dish Network Corp. Chief Executive Charlie Ergen is relinquishing his role as president of the satellite-TV provider, freeing the billionaire co-founder from some day-to-day duties as he works on a plan to enter the wireless industry. Ergen will remain chairman and CEO, a title he retook just nine months ago, while company veteran Erik Carlson will become its president and chief operating officer, the Englewood, Colorado-based company said in a statement.