At any time he may deem it necessary or advisable, the judge of any trial court of record may order a special term to be held, by written order filed with the clerk at least fifteen days before the opening of such term. Anything which may be done at a regular term may be done at a special term. Source: Supreme Court Rule 118, 1939; SDC 1939 & Supp 1960, § 33.1105.