Sprint ( S) lays the boom on top management with a big shakeup. The sputtering No.3 wireless telco says it has replaced three of its top chiefs in its ongoing effort to turn the business around. The move comes less than a week after Sprint's new CEO Dan Hesse announced he was cutting 4,000 workers and closing 125 stores. CFO Paul Saleh, marketing chief Tim Kelly and sales chief Mark Angelino are out Friday, replaced by acting chiefs William Arendt as CFO, John Garcia as marketing head and Paget Alves as sales chief. Hesse is conducting a huge review of the company's overall strategy and plans to name permanent positions at some later point. Among the moves Hesse is considering, say people familiar with the company, include deciding the fate of the so-called 4G WiMax unit, a migration of Nextel's iDEN customers to CDMA, a possible sale of the iDEN network and a potentially disruptive decision to change Sprint's monthly pricing plans. Sprint shares rose 15 cents to $8.87 Thursday.