Log into your phone system management console, refer to article below:
https://helpdesk.vcausupport.com/en-au/article/logging-into-vcloud-pbx-management-system/
Go to settings on the left

Select Timezone, Office Hours & Holidays

Scroll to the bottom to the Configure Holidays section

Press the Add button

Enter Name for the holiday, eg: Australia Day

Set the time range from when the holiday starts and ends

Press OK

https://helpdesk.vcausupport.com/en-au/article/logging-into-vcloud-pbx-management-system/
Go to settings on the left

Select Timezone, Office Hours & Holidays

Scroll to the bottom to the Configure Holidays section

Press the Add button

Enter Name for the holiday, eg: Australia Day

Set the time range from when the holiday starts and ends

Press OK

Published on: 12 / 01 / 2019