I got the answer from the Sage Support :

Backups can only be taken using the Estimating Management Console on the server with the Estimating Database. If your environment\IT department will not allow the application to be installed on the database server, your IT people will need to make a FULL SQL backup of the databases on the Estimating SQL instance.  

If your IT department is savvy enough to keep your SQL databases on a separate machine they shouldn’t have any problem creating a manual back.

Important: Backups created while databases are being accessed by other estimating users or applications will not be viable so make sure everyone is out of Estimating before creating your backups

So my users are not able to do backup from their workstation.