If a student's exam result has changed, following a remark from the Awarding Organisation, you'll need to record this change in Arbor.
The easiest way to do this is to go to the student's Student Profile and select Examinations from the left-hand side. Select Provisional statement of results.
On the next page, click the grade to edit it. Click Edit in the slide over.
Change the grade and value as needed, then click Save Changes.