KiwiSaver refunds can only be done in Ace Payroll if the contribution has not already been paid to Inland Revenue.
If you have not already paid KiwiSaver contributions to Inland Revenue, you can remove them from your PAYE Employer Deductions (IR345) and the Employer Monthly Schedule (IR348) to prevent them from being included with the rest of your payment.
This process is only possible for the first 2-3 weeks of employment for each employee. After that time the Reverse button will not be shown.
Any contributions that are sent to Inland Revenue before the employee opts out will be automatically repaid by Inland Revenue. In that case, you don't need to do anything.