10 U.S.C. § 1371 : US Code - Section 1371: Warrant officers: general rule

Search 10 U.S.C. § 1371 : US Code - Section 1371: Warrant officers: general rule

Unless entitled to a higher retired grade under some other
provision of law, a warrant officer retires, as determined by the
Secretary concerned, in the permanent regular or reserve warrant
officer grade, if any, that he held on the day before the date of
his retirement, or in any higher warrant officer grade in which he
served on active duty satisfactorily, as determined by the
Secretary, for a period of more than 30 days.