P.R. Laws Ap. tit. 32A, § III, Rule 58.6
The plaintiff may amend the complaint at any time before the trial of the issue of compensation and as many times as desired, but no amendment shall be made which will result in a dismissal forbidden by Rule 58.8. The plaintiff need not serve a copy of an amendment, but shall serve notice of the filing, as provided in Rule 67, upon any party affected thereby who has appeared, and in the manner provided in Rule 58.4, upon a party affected thereby who has not appeared. The plaintiff shall furnish to the clerk of the court, for the use of the defendants, at least one copy of each amendment, and he shall furnish additional copies at the request of the clerk or of a defendant. Within the time allowed by Rule 58.5 a defendant may serve his answer to the amended pleading in the form and manner and with the same effect as there provided.