You can open or close your availability in the calendar at any time.
Click on the plus symbol in the box for the date and time you want to make available for appointments.
From the list that opens, select 'Add Available Time".
You will see 'On/Off Available' on the selected box. This indicates that the time slot is open for appointments.
To close a date and time for appointments, click on the plus symbol in the box for that time.
From the list that opens, select 'Add Block Time'.
The selected box color will turn 'Gray.' This color indicates that the time slot is closed for appointments.