I have been working in an international NGO for 2.5 years as Supervisor.. Since my joining on February 2014 my attaindance time is 9am. This NGO runs medical projects, and maintains variable timings for staffs, but this timing had been fixed to them since their joining. Now suddenly without any valid explanation my employer is telling my attaindance time is suppose to be 8.45 AM. I will be marked late if i come after 8.45 am. Can an employer do this sudden change in timing without any proper reason?