(1)    The chief justice of the supreme court may assign any active supreme court justice, court of appeals judge or circuit judge to serve temporarily as a judge of the court of appeals or any circuit court to aid in the proper disposition of business in that court. The chief justice of the supreme court may designate and assign reserve judges under s. 753.075 to serve temporarily in the court of appeals or the circuit court for any county. While acting under a temporary assignment, an active or reserve justice or judge may exercise all the authority of the court to which he or she is assigned.

   (2)   The chief justice of the supreme court may exercise the authority under sub. (1) in regard to municipal courts for the purpose of:

      (a)    Assigning a case in which a change of judge is requested under s. 757.19 (5) or is required under s. 800.05 to another municipal judge or, if none is available, transferring the case to circuit court.

      (b)    Assigning cases in municipal court in which a municipal judge is incompetent, unable or fails to act, to another municipal judge, former municipal judge or former circuit judge. A judge to whom cases are so assigned may serve until the chief justice determines that the incompetency, inability or failure ceases, or until the term of the municipal judge expires or the vacancy is permanently filled under s. 8.50 (4) (fm), whichever occurs first. If no judge is available, the chief justice may transfer a case from municipal court to circuit court.

   (3)   The chief judge of any judicial administrative district may assign any circuit judge within the district to serve in any circuit court within the district.

   (4)   

      (a)    If a judge before whom a reported proceeding has commenced is unable to proceed, the judge to whom the case is assigned may proceed with it upon certifying familiarity with the record and determining that proceedings in the case may be completed without prejudice to the parties. Otherwise the judge assigned may grant a new trial or rehearing.

      (b)    If a judge before whom an action or proceeding has been tried is unable to proceed after a verdict is returned or findings of fact and conclusions of law are filed, the judge to whom the case is assigned may proceed with it unless satisfied that the duties cannot be performed without prejudice to the parties, in which event a new trial may be granted.

   (5)   Any assignment referred to in this section or SCR 70.23 may be requested or ordered by telephone to minimize disruption of court calendars and inconvenience to parties and witnesses.