my recent story here.

I redeemed HKG>YVR and LAX>HKG J class on 7th Aug
Suppose I was planning come back on 17th Aug, but CX only able to give me 16th. I redeem it anyway and told CS wait list for me (3+1 infant J tix)
On tuesday (14th Aug) I got an email from [email protected] title : Change of your booking status‏
saying
"Dear XXXX,
Your booking on Business Class of CX885 (LAXHKG), 17Aug12 has been confirmed. Please check details on Manage My Booking."
At the same time my wife got a SMS too, but not me (strange eh?)

So I quickly call MP/AM the 1-886 number (mind you the 800 doesn't work on stupid AT&T and T-mobile) and confirmed all 3 seats + 1 infant.

Easy as 1 2 3