How to prevent defaulting Contact & Bill to Contact on Sales order Header& Line from customer master

Hi,

We want the following highlighted fields to not default from Customer Master.

For customers with multiple contacts defined on the customer account and site level, only one contact is selected as the default on the sales order and the same values flows to AR Invoice, AR then sends an email specifically to this chosen contact from the order, rather than sending to all contacts defined on the customer. In order to ensure that all contacts receive the emails, we require a mechanism that will prevent defaulting the customer contacts on Sales orders.