Transaction DBITDH
This transaction is used to maintain the system holidays for a selected calendar.
The calendar function consists of two elements: one or several “system calendars” and the corresponding “public holiday calendar”.
The public holiday calendar indicates the public holidays relating to the selected year for the selected system calendar.

Below are the transactions allowed :

1.Add a new holiday to existing calendar

2.Modify or update an existing holiday

3.Delete an unwanted Holiday marked to calendar

4.Version log lists the modification associated 

Follow the below gif to maintain a system calendar