When you open a badge database which has a mirror available for it, you will see a dialog like this:

If you want to open the regular main database then select No. Select Yes to open the mirror.
If you open the mirror, note that you will be able to perform all operations as normal except those which would result in a change to the database. This means that you will not be able to revise existing, delete existing or create new badges. There will be other operations which will not be allowed also.
The previous paragraph will not be true, however, if you have configured the ID Badge program to allow the main database to be synchronized. If this is so, then you will be able to make changes to badge contents like text, photos, fingerprints, etc. but not perform any operation which would change the structure of the database, such as adding fields. See Synchronizing the Main Database for more details.