Troubled supermarket group Tesco is changing the chief of its executive pay committee.Tesco, which earlier this year replaced its group chief executive after its estimated profits were overstated by £263m, said Stuart Chambers would be replaced by non-executive director Deanna Oppenheimer on 1 January.Chambers, who has served more than four years as chairman of the chain's remuneration committee, will remain as a member of the committee and board to support the planned succession.Earlier this month, Tesco issued its fourth profit warning this year, saying annual profit would not exceed £1.4bn, against the £1.8bn to £2.2bn range expected by markets.The company has also said it is co-operating fully with a Serious Fraud Office investigation into past accounting practices.Former Unilever executive Dave Lewis, who joined in September and has replaced Philip Clarke as the group's chief executive, has since launched a management shake-up.