Hello there, info965.
To adjust a previously filed BAS period to match what you submitted to the ATO, you can reach out to our Customer Care Team. We can pull up your account and walk you through in making some changes.
Here are the steps:
You can also pull up reports to find BAS amendment (GST Exception) report to see if you are now in our new GST experience. You can use this article for reference: How to find the BAS Amendment (GST Exception) Report.
I'm here if you need more help. Take care!
When any change is made in periods prior to the most recently lodged BAS, they will be tracked and shown as amendments.
This includes periods prior to when GST was being used, as the system tracks everything prior to the most recently lodged BAS, it does not differentiate when GST codes started being used within a company.
However, I will be happy to provide feedback to the development team and ask them to revise the way the GST centre tracks amendments. If you wanted to provide similar feedback, you can do so within your company by selecting the Gear icon, and selecting Feedback.