"If you change your regional setting before you start the game, you will be able to get that region's Vivillon pattern. However, once your game has started, changing location doesn't work for getting another Vivillon pattern. You have to restart the game to get another pattern."
Source
As for Vivillions patterns:
Polar:
- Canada (Alberta, New Brunswick, Ontario, Saskatchewan, Quebec, Nova
Scotia)
- Sweden
- Norway
- USA (Alaska, Connecticut, Maine, Massachusetts, Michigan, New
Hampshire, New Jersey, New York, Rhode Island, Pennsylvania,
Wisconsin, Wyoming)
Savannah:
Tundra:
Source
Hope I helped :)