The time that your Diablo III client patches is determined by the region of the installer you used regardless of which Global Play region you play in. For example, players who installed Diablo III using the Americas' installer will patch according to the Americas' schedule.
Note: If your client patches ahead of other regions, you will be locked out of playing in unpatched regions until their patch goes live. This could mean that players in Europe who installed using the Americas’ installer may be locked out from playing in Europe if that region patches after the Americas. This applies for all regions.
If you would like to patch on a different region's schedule, you must reinstall Diablo III using your preferred region's installer. To download a different region's installer, go to the Game Client Downloads on your Battle.net Account Management page and select your preferred region.