P.R. Laws Ap. tit. 32A, § III, Rule 15.1
Every action shall be prosecuted in the name of the real party in interest, but a person authorized by statute may sue in his own name without joining with him the party for whose benefit the action is brought; and when so provided by statute, a claim for the benefit of another may be brought in the name of the Commonwealth of Puerto Rico. No action shall be dismissed on the ground that it is not prosecuted in the name of the real party in interest until a reasonable time has been allowed after objection for ratification of commencement of the action by, or joinder or substitution of, the real party in interest, and such ratification, joinder or substitution shall have the same effect as if the action had been commenced in the name of the real party in interest.