For some corrections in Attache it is easy to just reverse a pay and re-enter it correctly. However, if a pay component has been entered with the wrong tax selection, then it is more impacting and may have affected many pays.
You can setup a new correct Allowance code and then use an Adjustment to reverse the incorrect Allowance and replace it with the correct one. You will need to weigh up the tax and bank ramifications as this could be quite complicated. That is, you may need to repay an amount to the employee.
Work out the tax difference if this has been affected due to the incorrect setup. If the error was over several months, then you can enter the adjustment by month per employee.
Setup a new correct Allowance code in Setups, Payroll, Allowances, Maintain.
Create an Adjustment for the employee/s affected. Go to Payroll, Transactions, Adjustments, Create or Modify.
Select the Employee code.
In Function choose to Add new pay - start with an Empty Pay. OK.
Enter a Pay Description if needed. Check Accrue Leave is No. Accept.
Select the Allowance Line type to insert the original incorrect Allowance code.
Enter a negative value on this line (to reverse) and Accept.
Insert another Allowance Line type and the new Allowance code.
Enter a positive value and Accept.
Modify the tax value accordingly. This may need to be a negative or a positive value.
To simplify the process, you may decide to disregard the tax value and leave this for the end of financial year to right itself via the employee's tax return. However, if the employee underpaid tax, it is best to modify this in the adjustment.
A Bank line could be added to the adjustment if you intend on refunding the employee.
Check the Pays, entering the end of month dates if this how you are processing the adjustments or whatever period it relates to.
Select to include Adjustments only. Print.
Check and print your reports to ensure the adjustments are correct.
Process Pays and submit the STP batch to the ATO.