the simple cancellation of all the commitments will not take effect if one person signs on behalf of it. According to the relevant information, it is shown that the signature of the simple cancellation letter of commitment needs my signature to have legal effect, and the signing on behalf of it is not effective. The letter of commitment means that the promisor completely agrees with the offeror's offer and is expressed in written form. Usually, a contract is required to be concluded in writing, and its commitment must also be in writing. For example, Article 2-21, Part II of the Uniform Commercial Code of the United States stipulates that any contract for the sale of goods with a price exceeding $5, must be made in writing unless otherwise stipulated in the Code, otherwise the court cannot be required to enforce it. In principle, the court does not accept oral evidence for such contracts in litigation.