Making changes in QuickBooks Desktop after uploading file to TurboTax Business: Start over or simply re-upload?

After uploading the QuickBooks Desktop file to TurboTax Business and going through much of the process of creating the return, if you need to make changes to the source QuickBooks data, do you have to start the process from scratch, or can you upload the revised QuickBooks file and TurboTax readjusts for the changes/updates? A use case is to do what-if scenarios for moving expenses from the tax year to current year, or vice versa to determine impact on tax liability.