Changing the text after clicking a button in a modal

May I know how to solve my problem, how will it work if you click the button then the confirm button then the text “Hello” will change to a “Hi” word? I tried my best to solve it but I still can not know how to figure my problem that is why I am asking for a help. https://jsfiddle.net/chrismontage/dverj816/10/

<button class = "btn btn1" id = "myBtn">Button</button>

<h4 id = "message">
Hello
</h4>

<!-- The Modal -->
<div id="myModal" class="modal">

  <!-- Modal content -->
  <div class="modal-content">
    <div class="modal-header">
    
      <span class="close">&times;</span>
    </div>
    <div class="modal-body">
      <h4 class = "text-center">Are you sure you want to cancel your order?</h4>
    </div>
    <div class="modal-footer mx-auto">
      <button class = "btn" id = "confirm" onclick = "changeStatus()">Confirm</button>
      <button class = "btn" id = "cancel">Cancel</button>
    </div>
  </div>

</div>

/* The Modal (background) */
.modal {
    display: none; /* Hidden by default */
    position: fixed; /* Stay in place */
    z-index: 1; /* Sit on top */
    padding-top: 100px; /* Location of the box */
    left: 0;
    top: 0;
    width: 100%; /* Full width */
    height: 100%; /* Full height */
    overflow: auto; /* Enable scroll if needed */
    background-color: rgb(0,0,0); /* Fallback color */
    background-color: rgba(0,0,0,0.4); /* Black w/ opacity */
  }
  
  /* Modal Content */
  .modal-content {
    position: relative;
    background-color: #fefefe;
    margin: auto;
    padding: 0;
    border: 1px solid #888;
    max-width: 40%;
    box-shadow: 0 4px 8px 0 rgba(0,0,0,0.2),0 6px 20px 0 rgba(0,0,0,0.19);
    -webkit-animation-name: animatetop;
    -webkit-animation-duration: 0.4s;
    animation-name: animatetop;
    animation-duration: 0.4s
  }
  
  /* Add Animation */
  @-webkit-keyframes animatetop {
    from {top:-300px; opacity:0} 
    to {top:0; opacity:1}
  }
  
  @keyframes animatetop {
    from {top:-300px; opacity:0}
    to {top:0; opacity:1}
  }
  
  /* The Close Button */
  .close {
    color: white;
    float: right;
    font-size: 28px;
    font-weight: bold;
  }
  
  .close:hover,
  .close:focus {
    color: $color5;
    text-decoration: none;
    cursor: pointer;
  }

// Get the modal
var modal = document.getElementById("myModal");

// Get the button that opens the modal
var btn1 = document.getElementById("myBtn");

var confirm = document.getElementById("confirm");

var cancel = document.getElementById("cancel");

// Get the <span> element that closes the modal
var span = document.getElementsByClassName("close")[0];

// When the user clicks the button, open the modal 
btn1.onclick = function() {
  modal.style.display = "block";
}

confirm.onclick = function () {
    modal.style.display = "none";
}

function changeStatus() {
    document.getElementById("message").innerHTML = "Hi";
  }

cancel.onclick = function () {
    modal.style.display = "none";
}
// When the user clicks on <span> (x), close the modal
span.onclick = function() {
  modal.style.display = "none";
}

// When the user clicks anywhere outside of the modal, close it
window.onclick = function(event) {
  if (event.target == modal) {
    modal.style.display = "none";
  }
}





  

Answer

Just add one line to your confirm.onclick function:

confirm.onclick = function () {
    modal.style.display = "none";
    changeStatus();
}

You had the function right, just probably forgot to add it to your onclick listener.