How can I unlock a Sony BDP-S185 to allow it to play any region dvd's

You can use a DVD copy tool to get a DVD copy without region code so the DVD discs can be played by players from any regions. You can try Leawo DVD Copy which can copy DVD without quality loss.

When a DVD disc is created, it is encoded with a "Region number." The disc will only play on DVD players with the same Region number - for instance, a Region 3 disc won't play on a Region 1 player.
Region 1: U.S. and U.S. Territories, Canada
Region 2: Japan, Western Europe, Middle East, South Africa
Region 3: South Korea, Hong Kong, Taiwan, Southeast and East Asia Region 4: New Zealand, Australia, Pacific Islands, Mexico, Central/
South America
Region 5: Russia and the former Soviet Union, Africa, Indian
subcontinent, North Korea Region 6: China
The only way to get around the region codes, is to rip a DVD to your computer and remove the region code. Then burn the DVD to a DVD R. There are programs around on the net, but I'm not sure it is legal in all countries.
Google for the programs.
A DVD player sometimes allows you to change the region code once. But it not even would allow you to switch back after you changed it once.