Vodafone has announced big changes at the top of Cable & Wireless Worldwide (CWW) following its recent takeover of the firm.The Chief Executive of Vodafone Global Enterprise, Nick Jeffery, has been appointed as CEO of CWW, with immediate effect.Jeffery leaves his job as CEO of Vodafone Global Enterprise, which serves the needs of Vodafone's top 1,500 corporate customers.He originally came from Cable & Wireless, a firm he joined in 1991.The current CEO of CWW, Gavin Darby, will work with Jeffery to ensure a smooth transition before leaving the business at the end of October."Nick [Jeffery] is an excellent leader with a deep understanding of enterprise customers' needs, a track record in value creation and familiarity with CWW's business," said Vodafone Group Chief Executive Vittorio Colao.It is a similar story for CWW Chief Financial Officer Ian Gibson, acting Chief Technology Officer Dave Broady and acting HR Director Jane Little, who are all replaced by Vodafone managers, but stay on for the immediate period.