If you're DM you can change award tickets for free up to T-72. I'd probably book D1 now as two OW award tickets if you have lots of miles, especially if your dates aren't flexible. Then keep looking. If you can find partner space, it will cost far fewer miles. In addition to MU, look for DE award space through ICN, although there might be black out dates for KE award tickets using DL miles that will preclude this option. It also might be cheaper for instance to book for example SEA-PEK either with connections on DL from RDU to SEA or as a separate ticket, either paid with miles or with money.