First off congratulations on a cracking set of AS results. They are a tribute to all your hard work and hours of revision.
It is course the nature of examinations that some of you will want to target a re-sit in the January examination season. Your class teacher will give you a sheet with your unit break downs and the number of marks that you are away from the next grade boundary. There will be revision support closer to that date, but initially we would strongly recommend that if you are looking to redo a paper, then you should order your script (£9.50) from the examinations office. An appropriate member of the department will of course be happy to go through this with you.