You may set a temporary lock for a document to avoid conflicts when several authors concurrently edit the document. A locked document may only be read by other users, it cannot be modified or replaced. Also, a new version cannot be generated.
•      
Select 
  Access  
  Set 
Lock  in the action menu of the document and enter a 
lock note. Confirm by clicking [OK]. 
As lock owner, you may change the lock note any time 
without unlocking the document: click on the 
 icon in the ‘Share’ 
column of the document entry. Using this very action, you may also 
unlock the document again by hitting [Unlock]. Instead of clicking on 
the icon you may also invoke this action via 
  Access  
  Show 
Lock . 
If you want to modify a document that has been locked by another user in spite of the lock, you may ‘steal’ the lock, sufficient access rights given.
•      Click 
on the 
 icon in the ‘Share’ column of the entry of the document 
locked, enter your own lock note and confirm with [Steal lock]. 
Now you have locked the document for other users and may 
modify it yourself. The former owner of the lock will be notified via email. If 
you do not have sufficient access rights for stealing the lock, only the lock 
note will be shown to you. Stealing (or viewing) the lock may also be invoked by 
selecting 
  Access  
  Show 
Lock  in the action menu of the document locked. 
When you lock a document that you do not own, you become an additional owner of the document.