When you use the ERM Import Payment window to import a payment from a csv file, the source csv file being imported is then locked and cannot be renamed, or saved over, until the user exists GP.

Once the user exits GP the file again becomes available for rename or saving over.

It would be nice to be able to rename the file while you are still in GP
Under Review
Ideas Administrator

Thanks Terry, we will consider this functionality for a future release. 

Jodi Christiansen
PM, Microsoft