Accountancy software firm Sage revealed on Friday that its long-running Chief Financial Officer (CFO) is to leave the company with immediate effect, two weeks earlier than planned.Paul Harrison, who started at Sage back in 1997 and joined the board in 2000, announced his resignation in May at the time of Sage's first-half results though the company originally said he would leave on August 30th.He is stepping down to become the CFO of US software firm WANdisco.Harrison said in May: "I have every confidence that he and my colleagues will deliver on those plans and opportunities.  For me personally, it is the right time to seek a new challenge and I am very excited to be joining WANdisco."Shares in Sage were down 0.14% at 351.5p in early trading on Friday.BC