If you had shared a teammate's tasks iCal and no longer want them to have access, the following steps will revoke access to the current URL.
Hospitable will also generate a new URL. This means that if you've shared it elsewhere, such as on your own calendar app, you'll need to update this to the new iCal URL.
Go to Operations
Click on teammates
Click on the teammate's name
On the top right, next to Copy the iCal feed, click on the three dots
Click Reset access