how to change the size of a box collider in c#

im using a box collider but i want to change its size for when a new objects equiped so i was wondering how i can change a box collider size in c#

BoxCollider b = someGameObject.collider as BoxCollider;
if(b != null)
{
b.size = new Vector(1.0f, 1.0f, 1.0f);
}
//something like this should work

In 2022, the code provided by the previous answer is no longer working. The following code worked for me:

    BoxCollider col;

    void Start()
    {
        col = GetComponent<BoxCollider>(); 
    }

    private void OnMouseDown()
    {  
        if(col != null)
        {
             col.size = new Vector3(.5f, 1f, .5f);
        }
    }