Question How to move the target object of Inverse Kinematics

I have an object named leftHand thats children of the gun. and I want to move this Object to magazine's position. but when I move it , it goes to magazines position of course, but when the coroutine ends and the script moves leftHand to original position, it just stops and doesnt moves. In short, target Object moves once to wanted position and then I can not move it again.