When someone is listed as a beneficiary in a Will, they can "disclaim" or "renounce" their inheritance. For a disclaimer/renunciation to be valid it must be: in writing, an unqualified irrevocable refusal to accept any interest in the asset, and delivered to the executor within a certain period of time from the date of the decedent's death (this period varies from state-to-state). The Will then determines who inherits the disclaimed/renounced share.