If you have submitted a pension contribution CSV file and subsequently need to correct the file, you can select Cancel Statement and re-upload the correct CSV file. This option is only available on the same day that you uploaded the file.
If any corrections to the upload file e.g. underpayment or overpayment need to be made after the file has been submitted (and were not actioned on the same day as the upload), they will need to be reconciled in the upload file for the subsequent pay period.