The Element replaceChild() method replaces a child node with a new node.

<button onclick="my_function()">"Replace First Item"</button>

<ul id="my_list">
    <li>Lamborghini</li>
    <li>Ferrari</li>
    <li>Maserati</li>
</ul>

// function called by button click
function my_function() {
    // select first child element
    let my_element = document.getElementById('my_list').children[0];

    // create a new text node
    let my_node = document.createTextNode('Alfa Romeo');

    // replace the text node
    my_element.replaceChild(my_node, my_element.childNodes[0]);
}

- Alfa Romeo
- Ferrari
- Maserati

node.replaceChild(newnode, oldnode)