Here are the steps you'll need to take to reset the CPF file for re-downloading from the system:

1) Head to Payroll > Payroll settings > Month Total > Export Bank Payments/CPF/Reports and access the 'CPF' page:

2) In 'CPF' page, hit the "Reset CPF payment" button.

3) You should now be able to make the relevant adjustments to your CPF file in the system 😄