When the decedent dies testate but his testament fails to designate an executor, or the person designated is unwilling or unable to serve, all of the general or universal legatees of the decedent may agree on the advisability of having an independent administration and collectively designate a qualified person to serve as dative independent executor. In such case, the court shall enter an order granting independent administration and appointing the person designated in the application as dative independent executor.
La. C.P. § 3396.4