To unlock a branch

In the Version Tree Browser window, select the branch object.
Click Branch > Show lock to determine whether a branch is locked or obsolete. (The commands are unavailable until you select the branch object.)
A window indicates that shows whether the branch is locked, unlocked, or obsolete.
If the branch is locked, select the branch object.
Click Branch > Unlock. (The commands are unavailable until you select the object you want to unlock.)

The branch is now unlocked.