The handwritten modification of the contract shall be effective after both parties reach an agreement through consultation and sign it. For a handwritten contract, it is only valid if both parties press their handprints or sign beside it, and it is only valid if they don't sign or press their handprints, but both parties acknowledge that the revised content is the result of negotiation.

legal ground

Article 490 of the Civil Code If the parties conclude a contract in the form of a contract, the contract is established when the parties sign, seal or press their fingerprints. 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.