Export and Import Data into Microsoft CRM 2011 after changing the file type from XML to CSV

I am trying to export data from our Microsoft CRM and make changes on these data and import them again into the CRM. When I click on Export I click on the checkbox to include the columns required to return these data into CRM. However, our information company that process these files will need to change the file type from XML to CSV which will make the file not able to import again even when I change it to XML. Do you know what is the best way to solve this issue.