Once your payroll has been created, it is not possible to change the pay frequency from weekly to monthly, or vice versa. The Pay Frequency field in Payroll Settings will be inactive and not available for change. Before saving you will be prompted to verify if the details entered are correct.
If you need to change frequency mid year, you can create another payroll and manually migrate the data from one payroll to the other.
Please see Add Year to Date (YTD) information if you need help in entering the correct data.
When the new payroll is created and you are finished with the old payroll, please ensure you mark the employees as inactive.This will ensure the payroll information is not duplicated.