RCW 11.108.090

The personal representative, trustee, or any affected beneficiary under a will or trust may bring a proceeding under the trust and estate dispute resolution act in chapter 11.96A RCW, to determine whether the decedent intended that the references, presumptions, or rules of construction under RCW 11.108.080 be construed with respect to the federal law as it existed after December 31, 2009, including but not limited to the amendments made to federal law by the federal tax relief, unemployment insurance reauthorization, and job creation act of 2010, federal House Resolution No. 4853, P.L. 111-312. In making such determinations, extrinsic evidence may be considered, whether or not the governing instrument is found to be ambiguous, including but not limited to, information provided by the decedent to the decedent's attorney or personal representative. Such a proceeding must be commenced not later than two years following the death of the testator or grantor, and not thereafter.