If the contract was signed by others, if there is a power of attorney, it can be said that the intention signed in the Ming Dynasty is true and the contract is valid. A civil juristic act that meets the following conditions is valid:

1, the actor has corresponding capacity for civil conduct;

2. The meaning is true;

3, do not violate the mandatory provisions of laws and administrative regulations, do not violate public order and good customs.

In any of the following circumstances, the escrow agreement is invalid:

1. One party enters into an agreement by means of fraud or coercion, which harms the national interests;

2, malicious collusion, damage the interests of the state, the collective or the third party;

3. Covering up illegal purposes in a legal form;

4, damage the public interests;

5. Violation of mandatory provisions of laws and administrative regulations.

A civil juristic act in which the actor and the counterpart have false meanings is invalid. The validity of a concealed civil juristic act with false intention shall be handled in accordance with relevant laws and regulations. If a party commits a civil legal act that goes against its true meaning by fraudulent means, the injured party has the right to request the people's court or an arbitration institution to cancel it. If a third party commits fraud, causing one party to commit a civil legal act against its true meaning, and the other party knows or should know about the fraud, the defrauded party has the right to request the people's court or an arbitration institution to cancel it.

Legal basis: Article 144 of People's Republic of China (PRC) Labor Contract Law.

A civil juristic act carried out by a person without capacity for civil conduct is invalid.