JSFiddle - React, Tailwind, and code Playground
HTML
<select name="estado" class="selectpicker" data-dropup-auto="false" onchange="this.form.submit()" data-style="btn-danger">
<option value="0">Disponible</option>
<option value="1">Contratado</option>
<option value="2" data-toogle="popover">No disponible</option>
</select>
JavaScript
$(function () {
var pop = $('[data-toggle="popover"]').popover({
html:true,
trigger: 'manual',
content: function(){
return
"<form name='statusForm'>"+
"<div class='form-group'>"+
"<textarea class='form-control' name='estado' placeholder='Motivo de la no-disponibilidad' required></textarea>"+
"</div>"+
"<button class='button btn btn-success' type='button'>Aceptar</button>"+
"<button class='button btn btn-success' type='button' >Cancelar</button>"+
"</form>"
}});
});