How to Change a variable in another script when ontriggerenter

Hi, I am looking to change the jumpheight variable set by another script called "BallControl" when i enter a trigger, and im not sure how to do it. Here is what i have so far, but there are many errors and its not working whatsoever.

 function OnTriggerEnter (Collider) {
         BallControl BallControl = GetComponent<BallControl>();
         JumpHeight = 15();
 }

And here is what i have in my BallControl script

 var rotationSpeed = 100;
 var jumpHeight = 8;

 
 private var isFalling = false;
 
 function Update ()
 {
     //Handle ball rotation.
     var rotation : float = Input.GetAxis ("Horizontal") * rotationSpeed;
     rotation *= Time.deltaTime;
     rigidbody.AddRelativeTorque (Vector3.back * rotation);
     
     if (Input.GetKeyDown(KeyCode.W) && isFalling == false)
     {
         rigidbody.velocity.y = jumpHeight;
     }
     isFalling = true;
 }
 
 function OnCollisionStay ()
 {
     isFalling = false;
 }

Thank you in advance