If you already have a database called ‘Professional’, first open and rename it via: File> Database Management> Rename. If you are absolutely sure that you do not need this database anymore, you can move or delete it via Windows Explorer.
Download the SimaPro installation file to reinstall SimaPro. This will also reinstall the ‘Professional’ database, either in the default database location or any other location you specify. Note that if a database named ‘Professional’ already exists in that location, SimaPro will not install a new database to prevent loss of your data.