The altered part is invalid, and the rest is still valid. Altering the date of the contract without authorization is suspected of maliciously modifying or forging the contract, and the altered or forged place is invalid. The contract will take effect after it is signed. Need to modify or change, must be signed by both parties. If it is not signed by both parties, it is invalid. If the date is changed, the whole contract may be invalid because the validity period has expired, depending on the situation.

Legal analysis

The valid requirements of a contract are as follows: 1. The parties have the corresponding ability to conclude a contract. In principle, natural persons must have full capacity to sign contracts. If a person with limited capacity and a person without capacity cannot sign a contract in person, they should be signed by their legal representatives. A person with limited capacity may independently sign a pure benefit contract or a contract that is suitable for his age, intelligence and mental health; 2. Meaning is truth. The expression of a contracting party should truly reflect its inherent meaning of validity, that is, its meaning of validity is consistent with the expression. If the expression of intention is untrue, the impact on the effectiveness of the contract shall be determined according to the specific circumstances. In case of general misunderstanding, this contract is still valid. If there is a major misunderstanding, this contract can be changed or terminated. In the case that the contract is obviously unfair due to the danger of taking advantage of others, the contract can be modified or terminated. A contract concluded by fraud or coercion is invalid if it harms the interests of the state; If it does not harm the interests of the state, the contract may be modified or terminated; 3. It does not violate the legal and social interests; 4. The subject matter of the contract must be definite and possible. The possibility of the subject matter of the contract means that the contract payment may be realized. The determination of the subject matter of the contract means that the subject matter of the contract is determined or can be determined from the beginning.

legal ground

People's Republic of China (PRC) Civil Code

Article 143 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; (three) does not violate the mandatory provisions of laws and administrative regulations, and does not violate public order and good customs.

Article 490 Where the parties conclude a contract in the form of a contract, the contract is formed when the parties sign, seal or fingerprint it. Before signing, sealing or fingerprinting, one party has fulfilled its main obligations, and the contract is established when the other party accepts it. A contract shall be concluded in written form as stipulated by laws, administrative regulations or agreed by the parties. If the parties do not do this in writing, but one party has fulfilled its main obligations and the other party accepts it, the contract is established.