Changing permission levels for your calendar
Click Calendar in the navigation bar at the top right of the screen
Right click on Calendar on the left side of the screen located under my calendars
Select Permissions from the drop down list
Find the person whose permission levels you would like to change, select the desired permission level from the drop down list and click Save when finished
See Calendar permission levels for information on what each permission level allows
Removing access to calendar
From the same screen used above to change permission levels, find who you would like to remove and click the cross to the right of their permission level
When you have removed the person, click Save at the top of the page
This person will no longer be able to access your calendar
