The court may change the place of trial in the following cases:
             (1)      When the county designated for that purpose in the complaint is not the proper county;
             (2)      Where there is reason to believe that an impartial trial cannot be had therein;
             (3)      When the convenience of witnesses, and the ends of justice would be promoted by the change.

Source: SDC 1939 & Supp 1960, § 33.0306.