It depends. 1. Change the agreement. Both parties agree to change the validity of the agreement. Therefore, it is necessary to affix a new signature and clearly mark it. 2. Because the agreement or contract must reflect the unanimous will of both parties, it cannot be signed under the conditions of fraud, threat or coercion, and it cannot violate the principles of obviously unfair. If the contract or agreement is signed under coercion or threat, even if there are fingerprints of both parties and the third party, this agreement has no legal effect. As long as the agreement reflects the agreement of both parties, even if it is only signed and there is no third party, the agreement is legally binding. Article 502 of the Civil Code, a contract established according to law shall come into effect upon its establishment, unless otherwise provided by law or agreed by the parties. In accordance with the provisions of laws and administrative regulations, if the contract should go through the approval procedures, such provisions shall prevail. If the failure to go through the formalities such as approval affects the effectiveness of the contract, it will not affect the performance of the obligation clauses such as approval and the effectiveness of relevant clauses in the contract. If the party that should go through the formalities for approval fails to perform its obligations, the other party may require it to bear the responsibility for violating its obligations. The modification, assignment and dissolution of a contract shall be subject to the provisions of laws and administrative regulations, and the provisions of the preceding paragraph shall apply and shall be subject to approval.