Wyo. Stat. Ann. § 4-10-516
(a) The settlor, trustee or trust protector of an existing irrevocable trust may elect in writing to treat the trust as a qualified spendthrift trust under this article, and the protection accorded under this article shall relate back to the
date of the election subject to extinguishment of a creditor's claim with respect to a prior qualified transfer utilizing the procedures provided in W.S. 4-10-514, if:
(i) The trust is modified nonjudicially under W.S. 4-10-111 to conform to the provisions of W.S. 4-10-510 within one (1) year after the election; or
(ii) A petition is filed under W.S. 4-10-412 to conform to the provisions of W.S. 4-10-510 within thirty (30) days of the election.