Array Reordering?

I cannot use a List. I have a set amount of Elements in an array, don't need to add or remove any- just need to be able to switch the Elements to different positions in the Array.

For example, I have a check that looks for an empty array. If the array behind it (index i + 1 ) DOES have a value, then the array that has something in it will replace the one that has nothing.

I also would like to be able to reorder based on an Element's variable (int) and this needs to be done in an Update() function of some kind.

Here is an example of my code I'm working on.

friendsList is a custom class Array. friendLabel is a GameObject[] with UI elements in the children.

 for(int i = 0; i < friendsList.Length; i++)
             if (friendsList.ElementAt (i).frienduser != null)
         {
             friendLabel[i].SetActive(true);
             friendLabel[i].GetComponentInChildren<Text>().text = friendsList.ElementAt (i).frienduser + " \n *" 
                 + friendsList.ElementAt(i).friendStatusMessage;
 
             // turn their state into the corresponding sprite imge!
             friendLabel[i].GetComponentInChildren<Image>().sprite = statuses[friendsList.ElementAt (i).state];
         }
         else //frienduser is null
         {
             friendLabel[i].SetActive(false);
 
             if (friendsList.ElementAt (i + 1).frienduser != null) 
             {
                 //if we have something behind this slot that is not empty, replace this empty one with the full one!
                 //friendsList.Equals(friendsList.ElementAt (i + 1); // = friendsList.ElementAt (i + 1); Doesn't work. :  ^  (
             }
         }