In the case of health administrative punishment, the power of attorney of the parties only has the signature of the legal representative, and there is no official seal of the unit. Is the power of attorney valid? The power of attorney of a legal person must be stamped with the official seal of the unit and signed by the legal representative. If there are reasonable reasons why the signature of the legal representative cannot be provided, it may not be provided, but in order to maintain the rigor and accuracy of the case file, the signature of the legal representative may be provided at the request of the counterpart. If there is only the signature of the legal representative without the signature of the unit, the power of attorney of the legal person is invalid.