how to take a db into unrecovery mode and apply more log backups?

From: bing (bing_at_discussions.microsoft.com)
Date: 12/16/04 

Date: Thu, 16 Dec 2004 10:21:02 -0800

In SQL Server Enterprise Manager, I restored a db from its full, diff and two
log backups (there are 4 log backups for this db) and left the database
operational. But I did not find what I need in the restored db. So I wanted
to apply the rest two log backups to the db. What should I do to the
currently operational db so that I can apply more log backups on it?

Thanks,

Bing