Sec.  20.  Appointment  of  acting  prosecutor.  –  When  a  prosecutor, his  assistant  or  deputy  is  disqualified  to  act  due  to  any  of  the grounds stated in section 1 of Rule 137 or for any other reason, the
judge  or  the  prosecutor  shall  communicate  with  the  Secretary  of Justice in order that the latter may appoint an acting prosecutor.