{{ form_start(form, {'action': path('sonata_user_change_password')  }) }}
{{ form_widget(form) }}

<div class="form-actions form-group">
    <div class="col-sm-offset-3 col-sm-9">
        <button type="submit" class="btn btn-danger">{{ 'change_password.submit'|trans({}, 'FOSUserBundle') }}</button>
    </div>
</div>
{{ form_end(form) }}