1. Open Charge to which the payment should be applied
  2. On the Payments/Credits tab, click Unapply all Payments/Credits
  3. Click Save and Close
  4. Reapply the desired Credits/Payments
OR
  1. Open the Charge
  2. On the Payments/Credits tab, click Unapply all Payments/Credits
  3. Click Save and Close
  4. In Scheduled activity, open the billing schedule
  5. On the Schedule tab, make any changes to the generated amounts
  6. Click Save and Close
  7. Reapply the desired Credits/Payments