This error occurs because a student can only have one open National School Lunch Program record.
You cannot edit this record at CALPADS (change an F (Free) to an R (Reduced). If you need to edit the record (changing from F (Free) to R (Reduced) and the effective dates remain the same, you will need to delete the record and then re-add the record using the correct code value.
If a student is changing qualifications during the year, you can enter an end date on the one record and add a new record with the correct effective date. When you submit your next SPRG file, CALPADS will be updated.