Juvenile court erred by dismissing petition rather than allowing Agency to amend the petition to conform to proof provided at the jurisdictional hearing. The Agency filed a dependency petition when toddler Marcus fell out of a second story window while his father was asleep. At the jurisdiction hearing, evidence was presented showing that, when a neighbor knocked on parents’ apartment door, they did not immediately answer, and that they often let the minor play outside alone. Parents both abused drugs, and mother was never home. Also, they failed to make medical appointments scheduled for the minor and had a history of neglect. Counsel for the Agency and for the minor asked the court to amend the original petition to conform to the proof presented at the hearing. The court rejected the request and dismissed the petition, releasing the minor to his parents. The Agency and the minor appealed, contending there was no substantial evidence to support the juvenile court’s dismissal of the petition, and the court abused its discretion by refusing to amend the petition to conform to proof. The appellate court agreed and reversed. Code of Civil Procedure section 348 allows amendment to conform to proof as long as those amendments do not “mislead a party to his or her prejudice.” Here, the request to amend was based on facts known to the parents, i.e. their history of substance abuse, lack of appropriate parenting, and failure to attend to the minor’s medical needs. These facts, which were disclosed to the parents prior to the hearing, supported amendment of the petition. Reversal was therefore required for the juvenile court to adjudicate the matter once it granted the motion to amend the petition.