Originally Posted by dkerr

CX 883 has first class every day from 7/8 thru 7/14 (I just picked a random date and used expertflyer.com to check)

What you should do is get the CX record locator (by phoning either BA or CX) then you can manage your booking at the CX web site, including assigning seats. As CX just moved to the same reservation system that BA use it is possible that the record locator you already have for the booking at BA will work at the CX web site.

David