Log in to the Candidate Filing System and click on “Amend Mode.”  You should see a red band across the page that says, “AMENDMENT MODE.”  Make the necessary changes in the appropriate schedule(s) and file the report – all while remaining in the “AMENDMENT MODE.”  Reports submitted this way will be filed as an amended report.
Keep in mind that amended reports cannot conflict with the candidate’s and treasurer’s certification that the original report filing was true, complete, and accurate, and are for changes such as correcting typos or errors in names/addresses of contributors or vendors.  Conflicts with the candidate’s and treasurer’s certification for such things as failing to report contributions or expenditures in the original report will likely be fined by the Commission.