Move object on previous Path

hi I am bipin chandra and i am using your astar path finding plugin. i want create to dynamic path and check the path is available or not. using following method
public bool CanPlaceObject(GameObject gameObject)
{
var guo = new GraphUpdateObject(gameObject.GetComponentInChildren().bounds);
var start = AstarPath.active.GetNearest(GameObject.FindWithTag(“Start”).transform.position).node;
var end = AstarPath.active.GetNearest(GameObject.FindWithTag(“Target”).transform.position).node;

    return GraphUpdateUtilities.UpdateGraphsNoBlock(guo, start, end, false);
}  

but meanwhile i want my object move on previous path not current path because i am created placement of temporally obstacle not permanent.placement. after click on final placement than change new path.

Regrads
Bipin Chandra