When a prisoner has served the minimum term of imprisonment required by law, the Bureau of Prisons may petition the responsible Regional Commissioner for reopening the case under §2.28(a) and consideration for parole prior to the date set by the Commission at the initial or review hearing. The petition must show cause why it should be granted, i.e., an emergency, hardship, or the existence of other extraordinary circumstances that would warrant consideration of early parole.
28 C.F.R. §2.15