Originally Posted by JAaronT
There is an option to un-checkin on the website, but if you click it, it will warn you that you should only do it if you're planning on canceling your trip completely.
That's *NOT* correct!!! 
It's pretty harmless to do a un-checkin. It does *only* a un-checkin. Nothing else. After that you can proceed to re-checkin. If you don't want to click on that button yourself, then you can always call Web Support and let them do it.