Originally Posted by
nas6034
Usually when you add on a leg does the class of service (F) become available so you can book it? e.g. USA-HKG F initially, rebook to USA-HKG(F)-ASIA(F/J/Y). Or is there a significantly high chance the F seat will disappear upon rebooking?
There is no seat to appear/disappear; the agent is reissuing your ticket by trading in the existing ticket and adding a leg to your existing reservation (all changes like this are a reissue with a new ticket number). Unless they screw up bigtime nothing "disappears", a new ticket is issued with the new flights added. I've done this plenty of times on AS (the same process applies on ALL AS award tickets, not just CX) and not once has there been a "whoops, your original flight's gone away".