If there is going to be any change in the normal schedule and you have adequate time to communicate such change, it is always better to put the employees on notice of the change well in advance, whether it is about a holiday, a working day, or any other. If the change crops up suddenly, leaving not much time for you to give advance notice, you have no option but to communicate such change as early as possible, making the best use of modern communication tools like SMS, etc. Thus, there is no hard and fast rule regarding advance notice of a holiday if it is a normal administrative decision and is guided by the principles of expediency and reasonableness.
Regards,
B. Saikumar
HR & Labour Law Advisor
Mumbai