N.D. Cent. Code § 3-01-08

A ratification can be made only in the manner that would have been necessary to confer an original authority for the act ratified or, when an oral authorization would suffice, by accepting or retaining the benefit of the act with notice thereof. A ratification is not valid unless at the time of ratifying the act done the principal has power to confer authority for such an act and ratification of part of an indivisible transaction is a ratification of the whole.