what to call? could not find in rulebook!

[Steve M]

Maybe I'm picturing this differently, and I'm definitely looking as a fastpitch guy. If this runner has stopped and the ball been returned to the pitcher and all other play appears stopped and THEN the runner decides to head back to his previous base, I've got an out. If, however, runner never really stopped - this is all continuous, then he's safe at his previous base.