If you have accidentally imported your schedule to Google Calendar instead of subscribing to it there is a way to remove the imported dates and leave your personal data from before the import.
When a schedule is imported instead of subscribed, the Google Calendar will show the events on the same calendar. This will not allow your calendar to sync and may be hard to see around your personal events.
To remove the imported events:
1. Open the ics file you downloaded in a text editing program such as Notepad or TextWrangler.
2. Use the Find/Replace tool to find "STATUS:CONFIRMED" with "STATUS:CANCELLED" and save the ics file again.
3. Go to Google Calendar and open your settings by clicking the Cog icon and "Settings."
4. Click Import Calendar
5. Open the file you changed and import it to the calendar again.
6. Click "Back to Calendar." Your calendar will now show only your personal events and not the subscribed events.
Now you can use the link in your subscription email to subscribe to your calendar. The subscribed calendar will be listed separately and will show in a different color. It will also update at midnight if there are any changes made during the day.