Read the full details at KB17542 - How to reload missing BlackBerry smartphone data into the BlackBerry Manager ... however here's an example of how to actually use it.

Download the BRK Tool SyncRequest.exe and run the command: SyncRequest -n SQLServer -db BESMgmt -sync "Handheld Agent" -value_type emailaddress hdawg@port3101.org

Where:

-n = hostname of SQL server hosting your BlackBerry Configuration Database
-db = name of your BlackBerry...