If you are a professional user, use the "CallQueue Operator" cube.
Open the cube and management and click "Settings".
Through settings, manage your greeting, opening hours and the company leave days.
Select the module "Holidays" and you are shown a calendar view.
Highlight a closing day by clicking on it. The day turns red.
By clicking again, you remove the leave day. Your settings are saved automatically. On days off, customers cannot start a video call.