Thanks everyone for your replies. I booked the flights going there with Korean Air and returning with Delta, using 105,000 miles per person. My husband and I are traveling there. There was no availability in returning with Korean Air. There was an option to use China Eastern but not China Southern on the return but taxes/surcharges were so high. It was cheaper to transfer miles from my husband’s account and take advantage of the bonus double miles to book the flights. Thanks again! We’re so excited to visit Southeast Asia and with a long stop in Seoul to visit the city in 10 hours.