John Wood Group's chief financial officer (CFO) Alan Semple said on Thursday he plans to step down at the oil and gas services firm's annual general meeting in May 2015.David Kemp, CFO of Wood Group PSN will succeed Semple, who has been with the company for more than 19 years.Ian Marchant, chairman of Wood Group said: "As a long-term member of the board, Alan has played a significant role in shaping Wood Group into the company it is today, having been heavily involved in the transition from a private to a public company in 2002 and the significant growth and internationalisation of the business over many years. I have enjoyed working with him and on behalf of the board, wish him the best in his retirement."The firm is also creating a new role of chief operating officer. Robin Watson, currently chief executive of Wood Group PSN will take on the role during the first half of 2015 with responsibility for Wood Group PSN, Wood Group Mustang and Wood Group Kenny.The timing of this move will depend on appointing a suitable successor for Robin in his current role, the group said.Liberum gave the firm a 'sell' rating following the announcement."The succession looks well planned, as we would expect from Wood Group, and we do not expect any change in strategy or delivery," the broker said.Shares slid 0.22% to 677p at 10:17.