Louisiana Revised Statutes Tit. 9, § 1973. Shifting interest in principal

A. (1) Except as to the legitime in trust, the trust instrument may provide that the interest of an original or a substitute principal beneficiary of an irrevocable trust vests in one or more of his descendants upon the death of the beneficiary either during the term of the trust or at its termination. The trust instrument may provide that the interest vests in another person if the beneficiary dies without descendants.

(2) With respect to the legitime in trust, the trust instrument may provide that the interest of an original or a substitute principal beneficiary vests in another person upon the death of the beneficiary either during the term of the trust or at its termination, only if a beneficiary dies intestate and without descendants.