Trial court erred in granting habeas petition without first issuing an order to show cause, warranting reversal. In 2012, Campbell was convicted of drug related charges, including several felony drug convictions. In 2015, Campbell’s Proposition 47 petition to reduce his six prior felony convictions to misdemeanors was granted. Campbell then filed a petition for resentencing under Penal Code section 1170.18, followed by a habeas petition titled, “For Proposition 47 Resentencing Only.” The habeas petition was filed pursuant to an expedited habeas procedure for Proposition 47 cases developed by the Orange County Superior Court. The district attorney’s office (OCDA) opposed Campbell’s habeas petition on procedural and substantive grounds, and the parties were permitted to file informal responses. At the next hearing, the trial court judge commented that he considered the “procedural aspects” waived, as the OCDA had not objected to the expedited habeas procedure during the two months it was being developed, despite being privy to all of the emails regarding its development. The trial court then granted Campbell’s petition, without issuing an order to show cause, and vacated the one-year sentences on Campbell’s six prior felony convictions. The People appealed. Held: Reversed and remanded. The OSC is an intermediate but vital step in the process of determining whether the court should grant affirmative relief requested by a habeas petitioner. (People v. Romero (1994) 8 Cal.4th 728.) It creates a “cause” and frames the issues. As the means by which a judicial proceeding is instituted, the issuance of the OSC is mandatory, not optional, and if the petition states a prima facie claim for relief, the opposing side must be given an opportunity to file a return. However, the court may grant relief without issuing an OSC where the right to file a return has been waived. “Waiver” is the “intentional relinquishment or abandonment of a known right.” In this case, even assuming the People failed to object to the expedited habeas procedure, there is no evidence they stipulated to waiving their right to file a return. Accordingly, the trial court was not relieved of its duty to issue an OSC.