Hi FMJ76,
Thanks for reaching out to us with this query.
Seeing as thought the reconciliation has already been done for this period, I would suggest to unlodge the BAS and then re-lodge using the correct GST codes.
If you are an accountant/bookkeeper user you are able to do this yourself, if not reach out to your personal QuickBooks accountant/bookkeeper who can do this for you.
Otherwise feel free to reach out to our customer support team that can help you unlodge this BAS.
You can reach out to a support agent using this link here - https://help.quickbooks.intuit.com/en_AU/contact
Kristian.