Update an order afterwards Have to update an order afterwards cause the client can choose a retail partner. 

&lt;form method="post" name="submitOrder" style="width: 100%" onkeypress="return event.keyCode != 13;"&gt;
  &lt;input type="hidden" name="action" value="commerce/cart/update-cart"&gt;
    {{ redirectInput('s/partner?number=' ~ number) }}
    {{ csrfInput() }}

    &lt;input type="text" id="retailPartner"
           name="fields[orderCommercePartner][]"
           value="0"&gt;

    &lt;input type="submit" 
           class="a-button  a-button--black  a-button--bold js-chooseThisPartner"
           style="margin-bottom: 40px;"
           value="{{ 'Choose this partner' | t }}"&gt;
&lt;/form&gt;


That's my form I fill the value fields[orderCommercePartner][] via JS and it's filled. 

But the order is not updated. Any Ideas what goes wrong here.
Orders can not be updated after they are completed. The only way around this at the moment is if a plugin used it's own controller action to update the order.

Please submit a feature request here: https://github.com/craftcms/commerce/issues