Question: Is it possible to allow users to edit orders once they have been submitted for approval? Or allow them to clone/copy them?
Answer: Unfortunately, it is not possible that users can reorder their orders before they are approved.
Though, there are few workarounds that we can do to avoid this:
#1 We can approve the order to allow them to reorder it again with the updated details and later can cancel the original one to avoid any confusion. (Please note: it is possible on approval and not on denial of the order).
#2 Unfortunately, as it is not possible that users can reorder their orders before they are approved, hence, we would recommend using instructions (checkout page instructions) available in the site settings to instruct the users for appropriately placing the order to avoid reordering.
Admin > Site > Settings > Instructions > Checkout Page Instructions.
#3 If approver has the option allowed to edit then the approver can also update the order with the correct details and then approve it.