Section 122(3) in The Bihar Panchayat Election Rules, 2006
(3)The oath/affirmation to Up-mukhiya and Up-Sarpanch shall be administered by the Mukhiya and Sarpanch respectively in the first meeting specified in sub-rule(2).Provided that, in the absence of Mukhia/Sarpanch, such oath/affirmation shall be administered by the Block Development Officer or by an officer authorised by the District Election Officer.