Change the scale with OnCollisionEnter once

When my player collided with a button"GAMEOBJECT" change the scale to big and the button is actived When i collide again change my player scale to small and the button is disabled. How can i do that?

 //My player
 public GameObject Player;
 //Materials
 public Material[] material;
 Renderer rend;
 void Start()
 {
     //RenderMaterial
     rend = GetComponent<Renderer>();
     rend.enabled = true;
 }
 private void OnCollisionEnter(Collision coll)
 {
     //Change to Big
    if(coll.gameObject == Player)
     {
         rend.sharedMaterial = material[0];
         Player.transform.localScale = new Vector3(5, 5, 5); 
     }
    //Change to Small
    if (coll.gameObject == Player)
     {
         rend.sharedMaterial = material[1];
         Player.transform.localScale = new Vector3(1, 1, 1); 
     }
 }

Just make a bool.

edit: Decided just to put the complete thing…

 private void OnCollisionEnter(Collision coll)
      {
          //Change to Big
         if(coll.gameObject == Player)
          {
    if(isBig)
    {
              rend.sharedMaterial = material[0];
              Player.transform.localScale = new Vector3(1, 1, 1); 
isBig = false;
          }
    else
    {
     rend.sharedMaterial = material[1];
     Player.transform.localScale = new Vector3(5, 5, 5); 
 isBig  = true;
          }
      }