14 U.S.C. § 735 : US Code - Section 735: Promotion; acceptance; oath of office

Search 14 U.S.C. § 735 : US Code - Section 735: Promotion; acceptance; oath of office

(a) A Reserve officer who has been appointed under this
subchapter is considered to have accepted the appointment unless
delivery thereof cannot be effected.
(b) A Reserve officer who has served continuously since taking
the oath of office prescribed in section 3331 of title 5, is not
required to take a new oath of office upon appointment in a higher
grade.