(1) If one or more minors has been appointed as executor jointly with other executors, a grant of probate may be made to the executors who are not minors with power reserved to the minor executor or executors who shall be entitled to apply for a grant of probate on attaining the age of 18 years.
(2) If the executor or executors who are not minors renounce or, on being cited to accept or refuse a grant fail to make an effective application for a grant, an appointment may be made under rule 37.