You have a responsibility to keep your ABN details up to date. You can update your details online or by contacting the ABR. If your business structure changes you may need to cancel your ABN.
It is important to update your information within 28 days of becoming aware of any changes to your ABN details.
If you are no longer entitled to an ABN it is important that you cancel it.
If your business structure changes you may need to cancel your ABN and apply for a new one.