Hello margaret-mccarth,
When you prepare and lodge your BAS in the QuickBooks Online GST center, the GST center will show all transactions with the GST code from a specific period and show any amendments from the previously lodged BAS. I'd recommend checking your BAS/GST Amendment Report, GST Detailed Report, and Transaction by Tax Code report and comparing them.
If you need to make a GST adjustment for a previously lodged BAS, you can either create an adjusting journal or edit the previous transaction entered for the said period. Or you can request to unlodge the previous BAS to account for the exceptions from the previously lodged BAS.
To create an adjusting journal, click on + New and click on Journal Entry. However, it's best to consult your accountant on what account to use to balance the adjustment journal to avoid messing up your books. Just make sure in creating the adjusting journal make sure to use the date within that lodged period and list the corresponding tax code. After creating the adjusting journal, the system will show this as an amendment to the current BAS period trying to lodge.
You can check this link to learn more about BAS amendment and unlodging BAS in QuickBooks Online:
You can also reach out to our Customer Care Team to help you with checking the BAS period affected and how to unlodge the BAS.
Feel free to post again in the Community if you have more questions. I'll be around to help you!
