8 C.F.R. § 1240.16
The Attorney General shall have the sole discretion to apply the provisions of section 309(c) of Public Law 104-208 , which provides for the application of new removal procedures to certain cases in exclusion or deportation proceedings and for the termination of certain cases in exclusion or deportation proceedings and initiation of new removal proceedings. The Attorney General's application of the provisions of section 309(c) shall become effective upon publication of a notice in the FEDERAL REGISTER. However, if the Attorney General determines, in the exercise of his or her discretion, that the delay caused by publication would adversely affect the interests of the United States or the effective enforcement of the immigration laws, the Attorney General's application shall become effective immediately upon issuance, and shall be published in the FEDERAL REGISTER as soon as practicable thereafter.
8 C.F.R. §1240.16