Payroll information cannot be modified after the payroll has been executed. Such changes can lead to differences in the compliance calculations, and it is often not possible to make modifications retrospecively. 

Hence, if you need to make changes to past payroll that has already been executed, we suggest that you make the required changes to upcoming payrolls. For example, if an employee's salary needed to be increased, then add the additional amount for payrolls that have already been executed as arrears in an upcoming payroll. That way, your past calculations will not change, and the employee will get the required modifications in their next payroll.