At time CX releases to Alaska, if I book on CX from JNB to HKG and then wait until the next day to book HKG to SFO (because HKG won't be available yet because it starts on the following day) I it appears I will have two reservations. Can I merge the two or will they be completely separate? As I am checking luggage this is a concern. Especially with a 10 hour layover and I don't plan on leaving the airport. If I have to collect bags and then check in and recheck bags for new flight, will I even be able to check in 8 hours (after immigration etc) before flight?