CARROLL — A Select Board member is stepping down. Rob Gauthier announced his resignation from the board on Tuesday for professional reasons. It is effective May 9. A 35-year U.S. Postal Service employee, Gauthier and his family will be relocating to Portland, Maine, where he has accepted a district executive position overseeing 145 post offices and 1,000 employees. Gauthier, 54, arrived in the North Country from southern New Hampshire in 2006 and moved to Carroll in 2012.