Originally Posted by
demue
Seems the best course of actionfrom a cost point of view to position yourself to CMB.
Changes to routings are usually only permitted on very expensive fully flex fares. A common misconception that "changes" means any type of changes. It does not.
I suspect, looking at fare rules for the D class from Sri Lanka, then changing
destination may not result in a significant difference, so changing from EWR to LAX for example, might only result in change fee + a bit extra. As you indicated earlier, changing country of origin will almost always result in tears though, as still need to issue ticket from original departure country (point of sale).
Other places, with reasonable business class fares, with point of sale = CMB, include CCU, BLR (cheapest) and then RGN & SGN. Might be worth checking these, particularly latter two, as they are obviously closer to BKK than CMB from a positioning viewpoint.