When the office of President of a District Forum, State Commission, or of the National Commission, as the case may be, is vacant or a person occupying such office is, by reason of absence or otherwise, unable to perform the duties of his office, these shall be performed by the senior-most member of the District Forum, the State Commission or of the National Commission, as the case may be:
Provided that where a retired Judge of a High Court is a member of the National Commission, such member or where the number of such members is more than one, the senior-most person amongst such members, shall preside over the National Commission in the absence of President of that Commission.]