ER 1.9. Duties to Former Clients

(a) A lawyer who has formerly represented a client in a matter shall not thereafter represent another person in the same or a substantially related matter in which that person's interests are materially adverse to the interests of the former client unless the former client gives informed consent, confirmed in writing. (b) A lawyer shall not knowingly represent a person in the same or a substantially related matter in which a firm with which the lawyer formerly was associated had previously represented a client: (1) whose interests are materially adverse to that person; and (2) about whom the lawyer had acquired information protected by ERs 1.6 and 1.9(c) that is material to the matter; unless the former client gives informed consent, confirmed in writing. (c) A lawyer who has formerly represented a client in a matter shall not thereafter: (1) use information relating to the representation to the disadvantage of the former client except as these Rules would permit or require with respect to a client, or when the information has become generally known; or (2) reveal information relating to the representation except as these Rules would permit or require with respect to a client.