Lekoil's chief financial officer (CFO) David Robinson has stepped down from his role with immediate effect, the Nigeria-focused oil and gas explorer said in a statement on Monday.Robinson, who left the company for personal reasons, will be replaced on an interim basis by Valentine Ejiogu, the group's financial controller."As Lekoil prepares to move to the next stage of its development as an oil producing company, the time commitment for the CFO in Lagos will increase," said Robinson."With a family in Asia, this was going to become increasingly challenging and so I have decided this is the right the time to move on."Lekoil added that the search for a new chief financial officer was already underway and it would update investors in due course.