Movement Keys Help PLZ

Im using this simple movement keys script,i just wanna know how would i be able to edit this scrip so that i would be able to put it on another mc1 but when u press the keys mc2 moves. Or if anyone has another script thats betetr that would be cool.

on (keyPress “<Left>”) {
currentX = this._x;
this._x = currentX-2;
}
on (keyPress “<Right>”) {
currentX = this._x;
this._x = currentX+2;
}