Wondering how to go about booking a mix of paid and redemption tickets so they are on the same PNR.

In order to fly on a CX redemption ticket from the US, say LAX-HKG or SFO-HKG, I' always need to position from DTW. CX almost never can get partner award seats needed to position, so I always just buy them. There is risk; if the connection is missed on separate tickets, then it's my tough luck. To protect myself, I'll often fly into the originating city and just spend the night. (Also time for rebooking, etc). Wasteful, I know. But I can just work from hotel. Anyway...

Of course it's hypothetical at this point as Cathay is not releasing redemption seats. But if/when....

Let's say DTW-LAX-HKG. I am helping a friend and the overnight stay isn't really an option for him. So to be protected, I think he would need to call Cathay and try to book the entire route on a single ticket. Right?

Of course if he calls and they can find partner award space to get him to LAX... great. But if not, is it possible to do a combination of PAID and REDEMPTION on a single ticket? PAY for DTW-LAX, and the REDEMPTION LAX-HKG?

Is there any way to do this online (to avoid a few hours on hold...)

Any other creative suggestions?