Found in the QC Admin Guide and in the QC User's Guide:
Project Administrators can undo checkout for other users.
When an entity is checked out, you can undo the checkout to cancel your
changes. To undo checkouts for entities checked out by other users, you
must have the appropriate user permissions.
When you undo a checkout, any changes you made to non-versioned fields
while the entity was checked out are not cancelled and the new values
You can view a list of all entities you have checked out in the current
To view checked out entities:
1 Select Versions > Pending Check In, or click the Check In button on the right
side of the module toolbar. The Pending Check In dialog box opens,
displaying a list of all entities checked out by the current user in the current
To undo a checkout:
1 Select an entity, or press the CTRL key and select multiple entities for which
you want to undo the checkout.
2 Select Versions > Undo Check Out, or right-click the entity and select
Versions > Undo Check Out.
3 Click Yes to confirm.
Hope this helps.