Unless otherwise specified in the declaration instrument, if a declarant revokes a delegation to a person to direct the disposition of the declarant's last remains or ceremonies after the declarant's death, or if such person is unable or unwilling to serve, the nomination of such person shall be ineffective as to such person. If an alternate designee is not nominated by the declarant, § 264 of this title shall govern. This section shall not be construed to revoke the remaining provisions of the declaration instruments.