You can either zerolise in the employee data or zerolise in the employee's pay for the month. To zerolise salary, please follow the steps below:
Employment Details (permanent)
Go to the Core module, and click Employment Details.
Select the employee, and click Basic Rate.
Zerolise the salary or enter the adjustment with negative values to waive off.
Ensure the Total Wage shows as zero and click Save.
Pay Records (temporarily for current month)
Go to the Payroll module and click Pay Records.
Double-click the affected employee.
Click on the Allocated Basic Rate on the left.
Zerolise the amount and click Recalculate.