{% trans_default_domain 'FOSUserBundle' %}

{{ form_start(form, { 'action': path('fos_user_change_password'), 'attr': { 'class' : 'fos_user_change_password', 'novalidate' : 'novalidate' } }) }}
    {{ form_widget(form) }}
<div>
    <input class="btn btn-success" type="submit" value="{{ 'change_password.submit'|trans }}"/>
</div>
{{ form_end(form) }}