Ratification can be made only in the manner that would have been necessary to confer authority originally, or, where oral authorization would suffice, by accepting or retaining the benefit of the act with notice thereof. It is not valid unless at the time of ratification the principal has power to confer authority for the act.

Source: CivC 1877, §§ 1349, 1351; CL 1887, §§ 3972, 3974; RCivC 1903, §§ 1668, 1670; RC 1919, §§ 1250, 1252; SDC 1939, § 3.0105.