When the parties sign a contract, they usually leave some blank lines outside the standard terms in the contract for the parties to fill in the supplementary agreement. In practice, sometimes there will be cases where one party fills in the content that is beneficial to himself after signing, thus causing disputes. The focus of the dispute is generally the validity of the blank clause and the content that the parties fill in afterwards. Generally speaking, the filling of blank clauses should be presumed to be fully known when the parties sign or seal, unless there is evidence to the contrary.

Therefore, signing a blank contract is effective, but the legal risk is great. It is suggested that the parties should not sign blank contracts easily.

If a blank agreement has been signed, it is necessary to contact the other party in time to withdraw the agreement, then express the meaning of consensus between the two parties, and then sign another agreement with clear and specific terms.

If the other party fails to fill in the blank contract according to the contents agreed by both parties in advance, it should seek the help of a lawyer at the first time, collect fixed evidence and prepare for rights protection.

Legal basis: Article 465 of the Civil Code. Contracts established according to law are protected by law.

A legally established contract is legally binding only on the parties, except as otherwise provided by law.