Want to exchange EU code for US code.

[Calastir]

I'm just curious as to how you managed to keep your account on the English (US) setting

I logged into membership.square-enix.com and changed it.

The bigger is is that regardless of your setting 80% of the time it will log you into eu.square-enix.com instead of na.square-enix.com. You have to check the dropdown on the preorder page to make sure the links there are pointing to NA and not EU then try and redeem. I usually had to log in and out a couple times for it to be right.