The Presidential Election Petition Tribunal is now headed by Justice M. L Garba, who is the Presiding Justice of the Lagos Division of the Court of Appeal.
Garba, who appeared on the five-man panel for the first time on Monday, replaces the President of the Court of Appeal, Justice Zainab Bulkachuwa.
Bulkachuwa had withdrawn from the panel on May 22 following an allegation of likelihood of bias leveled against her by the Peoples Democratic Party and its candidate in the February 23 presidential election, Alhaji Atiku Abubakar.
The petitioners are challenging the victory of President Muhammadu Buhari and his All Progressives Congress in the election.
There are three other petitioners challenging the outcome of the poll.