the addon website_sale his this template:
        
    <template id="template_header_default" inherit_id="website.template_header_default">
        <xpath expr="//t[@t-foreach='website.menu_id.child_id']" position="after">
            <t t-call="website_sale.header_cart_link">
                <t t-set="_icon" t-value="True"/>
                <t t-set="_item_class" t-value="'nav-item mx-lg-3'"/>
                <t t-set="_link_class" t-value="'nav-link'"/>
            </t>
        </xpath>
    </template>
In my module i want to place that cart in another place,
basically i want to change that xpath expression to
<xpath expr="//t[@id='myid']" position="after">
I cant seem to find how to do it. On the forum i read that I only need to make a template with the id="website_sale.template_header_default" in my own module and that will override the existing template, but that does not seem to work.
I am probably overseeing the obvious
 
                        
The template and xpath expressions don't come through in your message. You may want to try again and escape the xml.
I mean, try putting those bits in a "code" block.
You can create code blocks in questions and answers by starting a line with "/". That will pop up a list of possible styles, and code is one of those.
updated