Section 306. Change of venue; procedure

The  bringing  of an action or proceeding in the wrong district in the
  county shall not be deemed a jurisdictional defect, but the court may of
  its own motion, and must on the motion of a  party  defendant,  transfer
  the  action or proceeding to a proper district in the county. The motion
  by the defendant for such relief must be made in writing and  on  notice
  and  must be filed with the clerk before or at joinder of issue. It must
  specify the district in the county to which the  defendant  desires  the
  action  or  proceeding to be transferred and must state under oath facts
  showing that ground exists for such transfer. In the absence  of  timely
  motion by the defendant, he shall be deemed to have waived any objection
  relating to proper venue.