; and (B) work in at least one local office of U.S. Immigration and Customs Enforcement. . (20) By redesignating section 443 ( 6 U.S.C. 253 ) as section 442. (21) By redesignating section 444 ( 6 U.S.C. 254 ) as section 443. (22) By striking section 445 ( 6 U.S.C. 255 ). (23) By striking section 446 ( 6 U.S.C. 256 ). (24) In the subtitle E heading, by inserting United States before Citizenship and Immigration Services . (25) In section 451 ( 6 U.S.C. 271 )— (A) in the section heading, by striking Bureau of and inserting United States ; (B) by striking the Bureau of Citizenship and Immigration Services each place it appears and inserting United States Citizenship and Immigration Services ; (C) by striking the Bureau of Border Security each place it appears and inserting U.S. Immigration and Customs Enforcement ; (D) in subsection (a)— (i) in the subsection heading, by striking of Bureau ; (ii) in paragraph (1), by striking a bureau to be known as the Bureau of Citizenship and Immigration Services and inserting the United States Citizenship and Immigration Services ; and (iii) in paragraph (2)(C), by striking Assistant Secretary and inserting Director ; and (iv) by amending paragraph (4) to read as follows: (4) Managerial rotation program The Director of United States Citizenship and Immigration Services shall implement a managerial rotation program under which employees of United States Citizenship and Immigration Services holding positions involving supervisory or managerial responsibility and classified, in accordance with chapter 51 of title 5, United States Code, as a GS–14 or above, shall— (A) gain experience in all the major functions performed by United States Citizenship and Immigration Services; and (B) work in at least one field office and one service center of United States Citizenship and Immigration Services.