Dear Vyas, the "change in service conditions" as contemplated under Section 9-A of the ID Act, 1947, and enumerated in Schedule IV, refers only to changes effected by the employer at his own will, which are indeed disadvantageous to the employees or result in relatively adverse conditions of service.
In this perspective, how can you come to the conclusion that a change in the existing minimum rates of wages of employees, revised as per the orders passed by the appropriate government under its statutory power, would be to the disadvantage of the employees covered by the Minimum Wages Act, 1948?