DEMOTING BACKUP ACTIVE DIRECTORY

Hi guys, i’m having a win2k3 PRIMARY and BACKUP Active Directories. The problem is, the replication on Backup AD was not done for quite sometimes because of network problems experienced by our backup AD.Currently the system users are gettings messages that the accounts have been expired.Now the network issue on Backup AD is resolved. How can I Update my backup AD with all information from Primary AD.
Basil S. Baligumya
MOFEA SDU – CSA