I have had Emeco tickets re-issued at HKG CTO, HKG ATO (twice) & BA T4 transit desk, in each case without any pre-warning. The HKG ATO is superb: 20-25 minutes each time, with the added advantge that you can either sit near the desk and watch all the CX cabin crew clocking in or go through to the lounge and they'll bring the ticket through for you. The HKG CTO was perfectly competent, but VERY slow - around 90 mins to do the reissue (essentially due to the tax calculation - my latest Emeco ticket has this much more explicitly). BA T4 transit desk was hard work: it took ages to explain and it took them a couple of hours to do (which, fortunately, I was able to spend in the Concorde Room before my next flight), plus they insisted on charging me GBP25 in addition to the US$75 change fee.