5 U.S.C. § 3345: Acting officer

the first assistant to the office of such officer shall perform the functions and duties of the office temporarily in an acting capacity subject to the time limitations of section 3346; notwithstanding paragraph (1), the President (and only the President) may direct a person who serves in an office for which appointment is required to be made by the President, by and with the advice and consent of the Senate, to perform the functions and duties of the vacant office temporarily in an acting capacity subject to the time limitations of section 3346; or during the 365-day period preceding the date of death, resignation, or beginning of inability to serve of the applicable officer, the officer or employee served in a position in such agency for not less than 90 days; and the rate of pay for the position described under subparagraph (A) is equal to or greater than the minimum rate of pay payable for a position at GS–15 of the General Schedule. did not serve in the position of first assistant to the office of such officer; or served in the position of first assistant to the office of such officer for less than 90 days; and the President submits a nomination of such person to the Senate for appointment to such office. such person is serving as the first assistant to the office of an officer described under subsection (a); the office of such first assistant is an office for which appointment is required to be made by the President, by and with the advice and consent of the Senate; and the Senate has approved the appointment of such person to such office. Notwithstanding subsection (a)(1), the President (and only the President) may direct an officer who is nominated by the President for reappointment for an additional term to the same office in an Executive department without a break in service, to continue to serve in that office subject to the time limitations in section 3346, until such time as the Senate has acted to confirm or reject the nomination, notwithstanding adjournment sine die. For purposes of this section and sections 3346, 3347, 3348, 3349, 3349a, and 3349d, the expiration of a term of office is an inability to perform the functions and duties of such office. Subject to paragraph (2), this section [enacting this section and sections 3346 to 3349d of this title, repealing former sections 3345 to 3349 of this title, and enacting provisions set out as a note under section 3301 of this title ] and the amendments made by this section shall take effect 30 days after the date of enactment of this section [ Oct. 21, 1998 ]. This section shall apply to any office that becomes vacant after the effective date of this section. Notwithstanding subparagraph (A), for any office vacant on the effective date of this section, the time limitations under section 3346 of title 5 , United States Code (as amended by this section) shall apply to such office. Such time limitations shall apply as though such office first became vacant on the effective date of this section. If the President submits to the Senate the nomination of any person after the effective date of this section for an office for which such person had been nominated before such date, the next nomination of such person after such date shall be considered a first nomination of such person to that office for purposes of sections 3345 through 3349 and section 3349d of title 5 , United States Code (as amended by this section).”