About reserved and unreserved checkouts
DevOps Code ClearCase® lets you choose between reserved and unreserved checkouts. You specify which type of checkout you want during the checkout process.
A reserved checkout gives you the exclusive right to check in a new version of the element. When you check out a file reserved, only you can make changes to the file. No one else can check out the file reserved.
Team members can modify the content. They just have to check out the file unreserved.
With an unreserved checkout, you may need to merge your changes at checkin time, if someone else checked in a newer version before you did. When you check out a file or directory unreserved, the file remains available for a reserved checkout. Other users can check out the file or directory with a reserved or unreserved checkout.