Code of Professional Responsibility and Accountability (CPRA)
Section 18. Prohibition against conflict-of-interest representation; former clients. - In relation to former clients, the following rules shall be observed:
(a) A lawyer shall maintain the private confidences of a former client even after the termination of the engagement, except upon the written informed consent of the former client, or as otherwise allowed under the CPRA or other applicable laws or regulations, or when the information has become generally known. (b) A lawyer shall not use information relating to the former representation, except as the CPRA or applicable laws and regulations would permit or require with respect to a current or prospective client, or when the information has become generally known. ( c) Unless the former client gives written informed consent, a lawyer who has represented such client in a legal matter shall not thereafter represent a prospective client in the same or related legal matter, where the prospective client's interests are materially adverse to the former client's interests.