You may leave a calendar at any given time.
The calendar will remain if there are still other members who are part of the shared calendar.
A calendar will only disappear when the last remaining member leaves the calendar.
How to leave:
- Tap the main menu button in the top left hand corner of the screen
- Select the calendar you wish to leave
- Tap the "Settings" tab in the bottom right hand corner of the screen
- Tap "User Settings"
- Tap "Leave Calendar"