Prevent survey results from different classes ending up on the same report

Our standard post-class evaluation is used for multiple classes as we modify the date for each event.  This is resulting in the reports including multiple dates from different classes which does not meet our needs thus our question is two-fold:

1. How do use the same survey but for different classes but keep them in separate files for accurate reports?
2. How do we resolve our previous responses and class the responses so they are sorted correctly thus the published reports will also be accurate?

Thank you for any and all suggestions!

Thanks for contacting us. 

Unfortunately, there is no direct way to change the form. You can download your form submissions as Excel, separate the data, and then import the data separately to create separate reports. 

Reference guides.- 

How-to-Create-a-Visual-Report-with-Your-Form-Submissions

How-to-Download-Form-Submissions-as-Excel-CSV-PDF

Regards,