A U.S. amateur call sign carries the number of the district where it was first issued, and it goes wherever its holder goes. K6SBR was born a California 6 call and is now keyed from the Colorado 0 district, eleven hundred miles east.
Why a Colorado station keeps a 6
The FCC divides the country into ten call districts. California is 6; Colorado, with the rest of the mountain and plains states from the Dakotas down to Kansas, is 0. The digit records where a call was first issued, nothing more. Operators are not required to change call signs when they move, and under the vanity system an operator may request a call from any district. So a 6 in Grand Junction is not a mistake. It is a California call that followed a family east.
The details of the two licenses, the 1990 death and the 2002 cancellation are on the history page. If you have a relative's old call sign in mind, the reclaim a family call sign guide walks through how Cody did it.