If you would like to remove your Google Calendar sync or switch the sync to a different Google Calendar, you'll first need to disable your existing sync.
Disabling the Google Calendar sync
(1) Go to your Calendar
(2) Click the gear icon in the upper right
(3) Select Sync Calendar... from the menu
(4) In the Sync Calendar dialog, click the "Disable" link below your active synced calendar
Note: The teardown of the sync could take up to 30 minutes depending on how much calendar information you have.
Once the sync is disabled, if you'd like to sync another Google Calendar, you can follow the steps detailed here.
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