SmartWall.cs

using UnityEngine;
using System.Collections;

public class SmartWall : MonoBehaviour {
    private Vector3 agent;
    private bool coroutineFlag = true, moveTargetFlag = true;
    private Vector3 initialPosition, targetPosition;

	// Use this for initialization
	void Start () {
        initialPosition = transform.position;
        targetPosition = GameObject.Find("MoveTarget").transform.position;
    }
	
	// Update is called once per frame
	void Update () {
        agent = GameObject.Find("Agent").transform.position;
        
        if ((Vector3.Distance(transform.position, agent) < 9f) && coroutineFlag && moveTargetFlag) 
        {
            moveTargetFlag = false;
            StartCoroutine(MoveWall(initialPosition, targetPosition));
        }

        if (Input.GetKey(KeyCode.R) && coroutineFlag && !moveTargetFlag)
        {
            moveTargetFlag = true;
            transform.position = initialPosition;
        }
	}

    IEnumerator MoveWall(Vector3 start, Vector3 target)
    {
        coroutineFlag = false;
        float u = 0f;
        while(u <= 1f)
        {
            transform.position = Vector3.Lerp(start, target, u);
            u += 0.05f;
            yield return null;
        }
        coroutineFlag = true;
    }
}