illegal. It is illegal for the company to require employees to change to part-time jobs. The company has no right to change the contract without the consent of the employees. The employees can negotiate with the company. If the negotiation fails, they can apply for arbitration or bring a lawsuit. The company's request to change from full-time to part-time job is an illegal act that violates the labor contract, and it should pay a certain amount of liquidated damages to the workers according to the situation of breach of contract.