A transaction involving a conservatorship estate which is affected by a substantial conflict between the conservator's fiduciary duties and personal interests is voidable unless the transaction is authorized by court order after notice to persons entitled to notice under RCW 11.130.420(6) or a subsequent order. A transaction affected by a substantial conflict includes a sale, encumbrance, or other transaction involving the conservatorship estate entered into by the conservator, an individual with whom the conservator resides, the spouse, domestic partner, descendant, sibling, agent, or attorney of the conservator, or a corporation or other enterprise in which the conservator has a substantial beneficial interest.