Is it permissible for a married woman to cancel a general power of attorney she had given to her husband if he is incompetent?

The basic principle of agency (wakalah) is that it is a non-binding contract, which can be revoked by either party at any time. Thus, the principal can dismiss the agent, and the agent can relinquish the agency. However, scholars have made specific exceptions to this. It is advisable to be gentle and not hasty in canceling the agency, in order to preserve the husband's feelings and the marital relationship, unless there is significant harm in delaying it.