You can mark a regular working day as a nonworking day or indicate if certain shifts are valid or not for a particular day. The exceptions that you indicate are only valid for that day.
For example, if the Fourth of July is a holiday for the organization, and it falls on a Friday, which is a normal working day, you can mark that particular date as a nonworking day.
As another example, if the organization has an extra shift for taking inventory on the last day of each month. You can create that shift and mark it as a valid shift for the last day of each month within your calendar's effective period.
To mark a regular working day as a nonworking day or vice versa, select the date you want from the Calendar Details pop-up window and choose the applicable exception from the Day Details frame.
To mark a default shift as valid or invalid: