SQ's agents been telling me that I can't do any changes because there aren't any seats open on LH. Called my TAs and they said there are plenty of availabilities, LH stated the same thing. It seems to me that SQ people are getting lazy and just telling pax to buzz off.. The story is that I wanted to change the rest of my RTW and asked for a 2 day earlier departure on all remaining legs. SQ SFO office said they don't see availability on LH and SQ, same thing with KF. But everyone else that I called stated that the entire week is open! What gives?