You can find "management" emails (goes to their executive assistants) with a little bit of googling. The more important question is what do you expect to happen by going to management that reservations isn't addressing already following policy?

An equipment change doesn't entitle to schedule change levels of protection unless your purchased product isn't available any longer (ie prem econ that was changed to non-PE equipment). Unless you've had a change of operating carrier (which others have mentioned regarding Air Japan being NH, which is frequently disclosed as the "operating carrier" on TYO-SIN NH flights from the outset) or a change in departure/arrival time by more than 30 minutes, you're unlikely to get treated like a schedule change, even by going the "management" route.