On December 2, 1992, the trial court dismissed a petition for personal injuries filed by Fern Mauldin and her husband, Ar-*140lan Mauldin. Plaintiffs alleged Fern Mauldin was performing jury service when she fell on a step while exiting the jury box. They did not allege there was a defect in the design or construction of the step. There was none. On undisputed facts defendant City of St. Louis has an absolute legal defense of sovereign immunity. Stevenson v. City of St. Louis School List., 820 S.W.2d 609, 612 (Mo.App. 1991) (citing Kanagaiva v. State by and through Freeman, 685 S.W.2d 831, 834-845 (Mo. banc 1985)). For the same reason an amended petition filed without leave on December 31, 1992 could not state a cause of action.

However, the legal file discloses the December 2, 1992 judgment was never set aside. Accordingly, the amended petition filed on December 31, 1992 was ineffective and the court lost jurisdiction on January 4, 1993. An order entered on March 17, 1993 which purported to grant plaintiffs leave to amend their petition was ineffective. A July 16,1993 judgment for City of St. Louis based on the amended petition and a notice of appeal filed on July 26, 1993 all occurred after the court lost jurisdiction. The notice of appeal was untimely. Rule 81.04(a).

Appeal dismissed.