When using the Calendar and Contacts Server plugin in WHM & cPanel, the default calendar name is cPanel CALENDAR. You can change this calendar name to anything else of your choosing.
1. Use Roundcube to login to the email account that the calendar in question belongs to.
2. Click the Calendar link in the left-hand side bar.
3. Click the menu button and select "Edit/Share calendar"
4. You can now edit your calendar name.