Generally, an agency is revocable at the will of the principal. The appointment of a new agent for the performance of the same act or the death of either principal or agent revokes the power. If, however, the power is coupled with an interest in the agent himself, it is not revocable at will. In all cases the agent may recover from the principal, for an unreasonable revocation, any damages he may have suffered by reason thereof.
OCGA § 10-6-33