Diageo announced that Nick Rose will stand down at the Guinness owner's AGM on 14 October and that Deputy Finance Director Deirdre Mahlan will replace him as Chief Financial Officer. Nick will remain with Diageo until the end of December 2010.Diageo Chief Executive Paul Walsh said: "Deirdre joined Diageo having worked for the Seagram Company since 1992. She has held a number of senior finance positions in Diageo including Finance Director of our biggest region, North America, and as Global Head of Tax, of Treasury and of Shared Services." "During this time Deirdre demonstrated to the Board that she has the ability to be Diageo's Chief Financial Officer and today I am delighted to announce her appointment. Deirdre will make a significant contribution to the finance function and to the Board and I and my colleagues look forward to working with Deirdre in her new role."Last week, the drinks brands giant reported a 12% rise in organic sales in the third quarter and maintained its full year guidance.