The chief judge of any superior court of this state may make a written request for assistance to the chief judge of any other superior court, a senior judge of the superior court, a retired judge, or a judge emeritus of any court. The request by the chief judge may be made if one of the following circumstances arise:
An active judge may, except as hereinafter provided, call upon a senior judge to serve in an emergency or when the volume of cases or other unusual circumstances cause such service to be necessary in order to provide for the speeds and efficient disposition of the business of the circuit.
Ga. R. Super. Ct. 18.2