A general power of attorney allows the agent to act on behalf of the principal in any matters, as allowed by state laws. The agent under such an agreement may be authorized to handle bank accounts, sign checks, sell property, manage assets, and file taxes for the principal. Unless the principal chooses to make a power of attorney durable, the authority granted to an agent ends in the event of incompetency or incapacitation of the principal. When a power of attorney is durable, that means there’s language within the document which states an agent’s authority continues to apply even after the principal becomes mentally incapacitated.