(Bloomberg) -- BYD Co., the Chinese carmaker partly owned by Warren Buffett's Berkshire Hathaway Inc., said Yang Longzhong, a vice president, resigned due to unspecified personal reasons and changes in the structure at the company.Yang has no disagreement with the board of directors and has nothing to bring to the attention of shareholders, BYD said in a Hong Kong stock exchange filing Thursday. Yang no longer will hold any position at BYD, the company said.