You need to update your blackberry with the new contacts in the Outlook. But you dont want any update to happen from blackberry to outlook, Correct ?
Once you open the desktop manager and then synchronisation options.
There select 2 things
1. Sync from Outlook to Blackberry (May be the options named as Import and Export)
2. In case of conflict select Outlooks wins.
But just to be on the safer side, take a backup before you start the sync.