Undo Check Out

To cancel a checkout and return the element to the state it was in before you checked it out, right-click the element in Eclipse and click Undo Check Out on the Team context menu, or click the Undo Checkout icon.

This option becomes active after you connect to ClearCase and select an element in Eclipse that is currently checked out to your view.  

Related tasks
Check in or check out files
Check In
Check Out