Hi BS95,

Once the ABN number is changed in the payroll settings, the changes will apply to all future pay runs and to the ATO when submitting Single Touch Payroll.

To update your ABN number:

1. Click on the Employees tab.
2. Click on Payroll Settings.
3. Click on Details.
4. Click on the ABN field and edit the information.
5. Click on Save.

You can also check this link to learn more about different scenarios if your ABN changes for a comprehensive information.

Please let me know if you have any additional questions. I'm always willing to assist.