oneworld - Changing AONE3 bookings from dummy dates

in February 2009 I booked an AONE3 ex ICN, commencing in September, and have flown the first 3 sectors. I am now in the UK.

The booking was through a TA in Seoul and the originating carrier was CX (ICN to HKG).

All remaining unflown sectors are on dummy dates as the travel dates I wanted were more than 360 days out from the booking date. The first of the next sectors is on BA

To change the dates from now on, am I best to do this through the TA who handled the booking, CX as the originating carrier or BA as the next carrier?

To change the dates from now on, am I best to do this through the TA who handled the booking, CX as the originating carrier or BA as the next carrier?

IMO, BA would be the last people to call for this. All your TA is going to do is call CX, so if your TA is competent, I'd stay with the TA. Otherwise, I'd call CX directly.