Hi !
I'm also interested by a way to do that.
I call EA (via chatroom) to make a one-time time zone change but they told me, to recap : "impossible, we can't do it and if we could we would do it" but recent posts (since march I guess) indicate that is really possible.
(I "moved" from GMT +2 to GMT + 11 so it's not a matter of "too little differences in time zones")
So if some people can help us ?
Here is what I read weeks ago Jom4 (official thread, I guess you have already found it) :
https://forums.galaxy-of-heroes.starwars.ea.com/discussion/168546/update-to-timezone-change-policy-for-extreme-changes-only
Thx