Hi N-S
Thank you for your post. I'm glad to assist you with this.
If you have already reported the first pay run to the ATO, all you need to do is to Reverse for the 3 employees. After that, you may create a new pay run with the correct details or calculations to have the report in ATO updated. If you are on STP 2, the reports that you send will overwrite or update the previous report if you made changes. If you already paid your employee in the first pay run that you've done, you can just create a new pay run for allocation or matching in the later part. If you haven't paid them yet, then you can just do your pay run again as well after reversing.
Note: You can only delete a pay if it hasn't been reported to the ATO.
Here are some Help Articles to give you more information:
Please feel free to post again. I'm happy to assist further.
If my response has answered your enquiry please click "Accept as Solution" to assist other users in finding this information.