trying to override the existing view of sales_order_lines from the form view. Keep getting xml errors here.

<record id="sales_order_line_modified" model="ir.ui.view">
    <field name="name">sale.order.form</field>
    <field name="model">sale.order</field>
    <field name="type">form</field>
    <field name="inherit_id" ref="sale.view_order_form" />
    <field name="arch" type="xml">
        <data>
            <xpath expr="/tree/field[@name='name']" position="replace">
                <field name="name" on_change="onchange_order_line(product_id,name)"/>
            </xpath>
        </data>
    </field>
</record>

Trying to add an on_change method and getting an XML Archetecture error. Any help would be greatly appreciated.