There is no way for users to replace file attachments. While they can add new file attachments, this leads to a long list of evolving documents. We don't want this – we only want the one, current version of a document attached to a issue. The only workaround is to have the administrator delete the unwanted documents. Right now, the administrator here is being tasked with deleting dozens of documents a day... Ideally, only the person that originally uploaded a document would be able to delete it.