I need to buy a flight to SYD for a family member. He will be studying abroad in Australia. I know when he will be flying there, however, is it possible to book an open return ticket? I would like to give him the ability to stay a few extra weeks, if he would like, after the program has ended. Does UA allow the booking of open ended tickets, and if so, do they have to be booked into a certain fare class?

Thanks