How to revoke Navigator access to Google or Microsoft

Google

Instructions via Google's Support page are:

1. Go to your Google Account.
2. On the left navigation panel, select Security.
3. On the Third-party apps with account access panel, select Manage third-party access. 
4. Select the site or app you want to remove.
5. Select Remove Access.

Microsoft

Instructions via Microsoft's Support page are:

1. Go to the calendar navigation pane at the side and use the context menu for the calendar name under My calendars
2. Right-click the calendar you want to unshare. Or, if you’re using a touch device, touch and hold the calendar name.
3. Select Permissions.
4. To stop sharing your calendar with a person, find the person you want to change permissions for and either choose a new level of permissions or select the delete icon "x" to remove permissions.
5. Select Save to save your changes, or Cancel to undo them.