I have this ajax that sends some form data to the server. within the ajax I have a getJSON. How can I send that same form data in the getJSON?

Code JavaScript:
<script>
function personal(){
       $.ajax({
           type: "POST",
           url: "settings_personal.php",
           data:     "first_name=" + document.getElementById("first_name").value + "&last_name=" + document.getElementById("last_name").value + "&email=" + document.getElementById("email").value,
           dataType: "json",
           success:  function (html) {
 
               var error = html.error;
               if (html !== "") {
                   $('.save-button').replaceWith('<div class="save-button"><input onclick="personal()" name="update_profile" type="button" value="Error :(" class="btn btn-danger btn-large"/>&nbsp;<input name="reset" type="submit" value="Reset" class="btn btn-inverse btn-large"/>')
               }
 
               if (html == "") {
                   $('.save-button').replaceWith('<div class="save-button"><input onclick="personal()" name="update_profile" type="button" value="Saved" class="btn btn-success btn-large"/>&nbsp;<input name="reset" type="submit" value="Reset" class="btn btn-inverse btn-large"/>')
               }      
 
               $.getJSON("settings_personal.php", function(result){
                   $.each(result, function(i, field){
                     alert(field);
 
                   });
                 });                  
           }           
       });
}
</script>