designated summons
(A)The term “designated summons” means any summons issued for purposes of determining the amount of any tax imposed by this title if— (i)the issuance of such summons is preceded by a review and written approval of such issuance by the Commissioner of the relevant operating division of the Internal Revenue Service and the Chief Counsel which— (I)states facts clearly establishing that the Secretary has made reasonable requests for the information that is the subject of the summons, and (II)is attached to such summons, (ii)such summons is issued at least 60 days before the day on which the period prescribed infor the assessment of such tax expires (determined with regard to extensions), and (iii)such summons clearly states that it is a designated summons for purposes of this subsection. (B)A summons which relates to any return shall not be treated as a designated summons if a prior summons which relates to such return was treated as a designated summons for purposes of this subsection.