code: public void updateCharging(String subscriptionId, String serviceContextId, long units) throws Exception {
      // Fetch existing Ro session
      ClientCCASession roSession = roSessions.get(serviceContextId);
  
      // Create and Send CCR (UPDATE)
      JCreditControlRequest updateCCR = createCCR(CC_REQUEST_TYPE_UPDATE, subscriptionId, serviceContextId);
      roSession.sendCreditControlRequest(updateCCR);
  
      switchStateMachine(SENT_CCR_UPDATE);
    }
docs: /*
  (non-Javadoc)
  @see org.mobicents.servlet.sip.example.diameter.rorf.RoClient#updateCharging(java.lang.String, long)