c# – Im having problems with changing my character controller height

Hi im making a simple game and when the player crouches/slides I would want to make the character controller to change size however when it changes to its smaller size it doesn’t go back to its original size after you release the crouch button.

using UnityEngine;

public class advancedMovement : MonoBehaviour
{

PlayerMovement basicMovementScript;
public float sprint = 5f;
public float slideSprint = 6f;
public float deceleration = 0.5f;

public CharacterController ccr_controller;
public float ControllerHeight;

// Start is called before the first frame update
void Start()
{
    basicMovementScript = GetComponent<PlayerMovement>();
}

// Update is called once per frame
void Update()
{
    if (Input.GetKeyDown(KeyCode.LeftShift))
        basicMovementScript.speed += sprint;
    else if (Input.GetKeyUp(KeyCode.LeftShift))
        basicMovementScript.speed -= sprint;

    if (Input.GetKeyDown(KeyCode.LeftControl))
    {
        basicMovementScript.speed += slideSprint;
        ccr_controller.height = ControllerHeight;
        ControllerHeight = 7f;

    }

    if (Input.GetKeyUp(KeyCode.LeftControl))
    {
        basicMovementScript.speed -= slideSprint;
        ccr_controller.height = ControllerHeight;
        ControllerHeight = 14f;
    }


  }

}