Im leader of a pvp guild and we all switched alliance. Our Guild was created 5 years ago on the alliance we were playing on and now we switched.
We paid money for the switches, transfered multiple chars per player.
Now our tabard is in a ugly semi white colour , wich ruins every outfit and we cant claim keeps anymore.
There was no warning or disclaimer about that either.
So i requested to zos, asking them to let the guilds alliance switch.
They can change guild names, so i was sure it wouldnt be a issue to do the Guild Alliance change either.
Thats what i got as response :

I get if you say you just cant do it - then it would be something i would be interested to get implemented as a nice feature, for the future.
BUT just being like "alliance choice matters'' while youre selling 30 Alliance change tokens to us, so we can use that paid mechanic to switch to the alliance and then being like but your guild functins are now not aviable anymore , is just bad. We feel lowkey punished by zos for switching our guild.
Like okay ? We made our Alliance Choice, the WHOLE guild switched together, you just made a lot of money with this, maybe just show some goodwill and help us with our request?
If we would want we could close the old guild and reopen it on the new alliance.
Then we loose the creation date, wich was 5 years ago ( a really long time for a pvp guild) + our guild bank stuff, unless we transfer it, our rank system, our guild notes.
Its not worth the effort.
But a Guild alliance swap should be possible imo, specially if youre OFFERING an Alliance change token.