Under agency law, either the principal or the agent has the power to terminate the agency relationship at any time, even though they have previously agreed that the agent’s authority will continue for a definite period. If the principal exercises this power, the agent has no right to continue acting for the principal, and could be subject to liability for so acting if it causes loss to the principal. Since your seller has clearly indicated that he no longer wishes you to act on his behalf, you should remove your sign and lockbox, take the listing out of the MLS, and discontinue any other activity that indicates you are still his agent. It is not required that the termination of your agency authority be in writing. However, just because a party has the power to terminate the agency relationship doesn’t mean they also have the right to terminate the contract by which the agency relationship was established. If either party’s termination of the agency relationship is in breach of the contract between them, that party may be held liable for any damages that the non-breaching party may be able to prove. Under Maryland law, termination rights must be spelled out in the listing agreement. The issue of what damages you might be entitled to recover is a complicated one, and an answer could well depend on the occurrence or non-occurrence of future events, such as whether or not the seller’s property is sold or placed under contract during the remaining term of the listing agreement. You would need to see your own lawyer to discuss the damages issue in detail.