; (2) reducing costs to the taxpayer by expanding the Screening Partnership Program; and (3) examining security screening programs of foreign partners to outline best practices for public private partnership for passenger screening. 519. Headquarters efficiency Not later than 1 year after the date of the enactment of this Act, the Administrator of the Transportation Security Administration shall seek to reduce by 50 percent administrative support contract costs for headquarters personnel. 520. Repeal of regulations Sections 1408, 1517, and 1534 of the Implementing Recommendations of the 9/11 Commission Act of 2007 are repealed. 521. Sensitive security information (a) In general Not later than 90 days after the date of the enactment of this Act, the Administrator of the Transportation Security Administration (TSA) shall— (1) ensure clear and consistent designation of Sensitive Security Information , including reasonable security justifications for so designating documents as such; (2) develop and implement a schedule to regularly review and update, as necessary, TSA Sensitive Security Information Identification guidelines; (3) develop a tracking mechanism for all Sensitive Security Information redaction and designation challenges; (4) document justifications for changes in position regarding Sensitive Security Information redactions and designations, and make such changes accessible to TSA personnel for use with relevant stakeholders, including air carriers, airport operators, surface transportation operators, and State and local law enforcement, as necessary