Call Modal from myModal.php to my index.php

I have 1 Modal in the file called myModal.php. I want to call this file from the index.php without redirecting it to myModal.php, that is, the mode (myModal.php) is executed, remaining in the index of the page.

I have tried with the code that I share below, but redirects me to the myModal page and it is not what I want, since I want to stay on the page from which I make the call.

Thank you for your attention.

//Archivo index.php

<div class="container">
    <div class="col-md-10 col-md-offset-1 text-center js-fullheight slider-text">
        <div class="slider-text-inner">
            <p><a data-toggle="modal" data-target="myModal.php#myModal" class="btn btn-primary btn-lg">¡Solicita tu Reserva!</a></p>
            <br>
        </div>
    </div>
</div>

// File myModal.php

<?php
require "class/Db.class.php";
require "class/Conf.class.php";
$bd = Db::getInstance(); 
?>


<div class="container">
    <!-- Modal -->
    <div class="modal fade" id="myModal" role="dialog">
        <div class="modal-dialog">
            <!-- Modal content-->
            <div class="modal-content">
                <div class="modal-header">
                    <button type="button" class="close" data-dismiss="modal">&times;</button>
                    <h4 class="modal-title">My Modal</h4>
                </div>
            </div> <!-- fin modal-content -->
        </div> <!-- fin  modal-dialog -->
    </div> <!-- fin  modal-fade -->