In any proceedings involving any estate which is being probated, or when a minor or incompetent person has a legal guardian, the administrator or executor of such estate, or the guardian of such minor or incompetent person, shall have authority to execute all instruments of conveyance of any degree of title to the State of Oklahoma or any agency or political subdivision thereof, or the United States Government or any agency thereof, on behalf of said estate, minor or incompetent person without other proceedings than approval by the judge of the district court endorsed on said instruments of conveyance and the amount of consideration shown thereon.