Fantastic Jarek!, The Genius work!
Instead, i can able to do it,
while(k--) {
if (myFound[k].parent.constructor.name !== "Cell")
// try {
// myFound[k].parent.parentStory; // error if parent == "Cel" so omited
myFound[k].changeGrep();
}
SPlendid, thanks to you.
@Chand