There are two types of court jurisdiction: original and appellate. Original jurisdiction exists whenever a court has the legal right to hear a case for the first time. Appellate jurisdiction exists whenever a court is hearing a case which is being appealed or brought to it from a lower court. The Virginia Supreme Court of Appeals has original jurisdiction in cases of habeas corpus, mandamus and prohibition. Habeas corpus is a court order which commands a person having another individual in custody to bring before the court the individual detained for the purpose of determining the legality of detention. A mandamus is a court order directed to subordinate courts, corporations, or the like, commanding them to do something therein specified. A prohibition is a writ or court order which legally restrains someone from doing some particular action. In all other cases in which the Supreme Court of Appeals has jurisdiction, it has appellate jurisdiction only. The General Assembly has the power to provide, from time to time, for a Special Court of Appeals whose chief purpose is to assist the Supreme Court of Appeals. Whenever a judgment or decree is reversed, modified or affirmed by the Supreme Court of Appeals, the court must state in writing the reasons for same and must keep such record on file with the case. In criminal matters, the court may direct a new trial. If the court believes that the accused should be discharged from further prosecution, in such instance, it has the right to order the case ended, thereby discharging such an individual from further prosecution. This court has no power, however, to increase or decrease the punishment of an accused person. In civil cases, the court may enter a final judgment.