title: how to update key of $_SESSION array with php variable value
body: <p>I have an issue I cannot seem to find the answer of anywhere. So I am placing it here.</p>
  
  <p>I have following variables stored in $_SESSION variables :</p>
  
  <pre><code>$_SESSION["pr_first_name"]  ="Thomas";
  $_SESSION["pr_middle_name"] ="Richard";
  $_SESSION["pr_last_name"]   ="Peterson";
  </code></pre>
  
  <p>Now I need to access, change and then save the <code>$_SESSION array</code> keys and their values. I have written the following code for this:</p>
  
  <pre><code>extract($_SESSION);
  </code></pre>
  
  <p>this gives me the variables with the name of <code>$_SESSION</code> keys, now I need these variables to be saved as further keys of <code>$_SESSION</code> arrays. How can I save the php variables as keys to <code>$_SESSION</code> array?</p>