Justice Mohammed Garba has replaced Justice Zainab Bulkachuwa on the Presidential Election Petition Tribunal.
Garba was the presiding justice of the Court of Appeal, Lagos division.
He made his first appearance on the five-man panel on Monday.
Bulkachuwa recused herself from participating in adjudicating petitions challenging the re-election of President Muhammadu Buhari on May 22 after she was accused of pre-conceived bias by Peoples Democratic Party (PDP).
Garba, in his welcome address, called for cooperation of all the parties involved in the case.
He promised to do everything to expeditiously hear the petitions in line with the nation’s laws.