If you are the owner of a calendar (for instance your own calendar name) then you will be able to delete this calendar if you wish by clicking on the 'Manage Calendars' button as shown below in red:
You will then see the calendars listed - those that you own will be listed under the 'My Calendars' section at the top and you will see the red delete button as shown below:
Select the calendar you wish to delete and click on the red delete button as shown below in red:
You will then see a confirmation message to confirm the deletion by clicking on 'Delete' as shown below:
The calendar will then be removed.
If you are unable to delete a calendar this is because the calendar is owned by another CRM user - you will either need to get them to delete the calendar or you can contact our Support Helpdesk so that we can remove the calendar for you.