Wyo. Stat. § 1-26-511: Purchase efforts waived or excused.

(a) A condemnor's failure or inability substantially to comply with W.S. 1-26-509 and 1-26-510 does not bar the maintenance of a condemnation action, notwithstanding timely objection, if:

(i) Compliance is waived by written agreement between the property owner and the condemnor;

(ii) One (1) or more of the owners of the property is unknown, cannot with reasonable diligence be contacted, is incapable of contracting and has no legal representative, or owns an interest which cannot be acquired by contract; or

(iii) Due to an emergency affecting public health or safety, there is a compelling need to avoid the delay in commencing the action which compliance would require.