I just booked a one way ticket for my helper to go back to samarang. The cheapest way is to book HK-Jarkata-Hk through agent here. Then book the domestic flight online from Mandala Airline or you call Garuda Air Call Centre in Indonesia. They will give you a booking reference no. I asked my helper's brother to pay at the Garuda office in Samarang and I paid her back in HK. It's a e-ticket. So she just need to present her passport when she checks in in Jakarta.