Many may view the attorney-client relationship as being unique amongst business associations given the potential for its longevity. Once one has found an attorney that he or she has faith in, he or she may continue to seek said attorney's advice and assistance on legal matters for many years (provided those matters fall within an attorney's scope of practice). There are times, however, where one's association with an attorney may simply be limited to an isolated event. Yet unlike other professional providers, an attorney's duties to a client do not end with the completion of his or her representation.
Per the American Bar Association's Model Rules of Professional Conduct, an attorney is limited in his or her availability to become involved in matters in which he or she has represented previous clients in the past. He or she cannot assume the representation of a new client regarding the same or a substantially similar issue if doing so could be materially adverse to the previous client's interests. Even if it is determined that said attorney's services alone do not represent a threat to the interests of the previous client, he or she cannot disclose any information during the course of his or her representation that could potentially disadvantage that client.
The responsibilities an attorney has to his or her former clients may not be limited to only those that he or she has personally represented, but may also be extended to people represented in similar matters by other members of his or her firm. Indeed, the ABA lists issues with concluding the attorney-client relationship amongst the most common ethics traps that legal firms may face. An attorney (or firm) can be relieved of the duties owed to previously clients is said give consent (in writing) to do so.