This change belongs to the labor contract, and you can agree or disagree. If you don't agree, you can terminate the labor contract, and then the unit will give you economic compensation.

Legal basis:

People's Republic of China (PRC) labor contract law

Article 35 The employer and the employee may change the contents agreed in the labor contract through consultation. Changes to the labor contract shall be made in written form. The revised text of the labor contract shall be held by the employer and the employee respectively.

Article 40 Under any of the following circumstances, the employer may terminate the labor contract after notifying the employee in writing 30 days in advance or paying the employee an extra month's salary:

(1) The employee is sick or injured non-work-related, and cannot engage in the original job or other jobs arranged by the employer after the prescribed medical treatment period expires;

(two) the laborer is not competent for the job, and he is still not competent for the job after training or adjusting his post;

(3) The objective conditions on which the labor contract was concluded have changed greatly, which makes it impossible to perform the labor contract, and the employer and the employee cannot reach an agreement on changing the contents of the labor contract through consultation.