Are there any restrictions on the employer in the matter of changing the service condition of his workmen?

If the employer proposes to effect changes in the service condition of the workmen employed by him in respect of any matter specified in Schedule IV that contains service matters like wages, hours of work etc., He must give to the workmen prior notice of 21 days before effecting the change.  Prior notice is given to provide them an opportunity to consider the effect of the proposed change and to represent their point of view on the proposal.