8 C.F.R. § 241.22
An alien who has been finally excluded pursuant to 8 CFR part 240, subpart D may at any time surrender himself or herself to the custody of the Service and shall surrender to such custody upon notice in writing of the time and place for his or her surrender. The Service may take the alien into custody at any time. An alien taken into custody either upon notice to surrender or by arrest shall not be deported less than 72 hours thereafter without his or her consent thereto filed in writing with the district director in charge of the place of his or her detention. An alien in foreign contiguous territory shall be informed that he or she may remain there in lieu of surrendering to the Service, but that he or she will be deemed to have acknowledged the execution of the order of exclusion and deportation in his or her case upon his or her failure to surrender at the time and place prescribed.
8 C.F.R. §241.22