Hi,

If you need to delete database, please refer the following

https://www.odoo.com/forum/help-1/how-to-delete-a-database-161005

https://www.odoo.com/forum/help-1/how-can-i-delete-databases-when-drop-from-manage-databases-says-the-operation-was-successful-but-the-database-is-still-there-124373

There is no such options for resetting the database by default, you will have to use any data cleaning custom application.

Regards