I’d like to book an award flight, RT to ICN on KE for late 2024, returning mid-January, 2025. While I can’t book the return yet, the outbound leg is bookable at the RT fare (70K; one-way typically priced at 35K).

Can I book the outbound leg now at 70K to secure availability, and then call when it’s possible to tack on the mid-January return leg “for free”? In other words, can I pay the round trip cost for the one-way now, then add on the return leg later without incurring an additional charge?

Thanks!