A player's time zone is determined by his/her location at the time of account registration. There are several major time zones and the round finish time can be different even for players in the same zone, for example, on the East and West coast of USA or opposite ends of Europe.

Unfortunately, there's no way we can change your time zone. We used to do this earlier for some players, but it happened to break their accounts. That's why we do not do this anymore.
Sorry for this inconvenience!