Wyo. Stat. § 17-16-807: Resignation of directors.

(a) A director may resign at any time by written notice or by electronic transmission delivered to the board of directors, its chairman, or to the corporation.

(b) A resignation is effective when the resignation is delivered unless the resignation specifies a later effective date or an effective date determined upon the happening of an event or events. A resignation that is conditioned upon failing to receive a specified vote for election as a director may provide that it is irrevocable.