P.R. Laws Ap. tit. 32A, § III, Rule 67.2
Whenever a party has appeared represented by an attorney, the service shall be made upon the attorney unless service upon the party himself is ordered by the court. Service upon the attorney or upon a party shall be made by delivering a copy to him or by mailing it to him at his last known address, or, if no address is known, by leaving it with the clerk of the court. Delivery of a copy within this rule means handing it to the attorney or to the party; or leaving it at his office with his clerk or other person in charge thereof; or, if there is no one in charge, leaving it in a conspicuous place therein; or, if the office is closed or the person to be served has no office, leaving it at his dwelling house or usual place of abode with some person not less than eighteen (18) years of age then residing therein. Service by mail is complete upon mailing.