How to return to position if key is not pressed?

Need to be more specific but I'll give an example in C#. Keep in mind this is a very basic example to get you started.

 using UnityEngine;
 using System.Collections;
 
 public class EXAMPLE : MonoBehaviour
 {
     Vector3 oldPosition;
     float speed = 5.0f;
 
     void Start()
     {
         oldPosition = transform.position;
     }
 
     void Update()
     {
         if(Input.GetKey(KeyCode.Space))
             transform.Translate(Vector3.forward * speed * Time.deltaTime);
 
         else if(!Input.anyKey)
             transform.position = Vector3.MoveTowards(transform.position, oldPosition, speed * Time.deltaTime);
     }
 }