The "Firm" calendar is automatically shared among all users on your account and is meant to house events and appointments that effect all members of your firm.
To manage the users who have access to the Firm calendar, find the Firm calendar in the Clio sidebar panel then click on the drop down arrow. Click on "Edit & Share Calendar" to open the Calendar edit form.
In the Calendar edit form, you can change the access level that users and groups have to view the Firm calendar by clicking the "Add Calendar Share" link. For more information on sharing calendars, click HERE.
If you do not wish to see the firm's calendar, simply check the box next to "Firm" in the right-hand screen. This will remove the firm's calendar from the calendar view. To see the firm calendar again, simply re-check the firm box.