If orders are moved from brokering queue to backorder queue in HotWax. Can it add promise dates to the items in the order after reading them from the PO as well?
And if yes, it can be communicated to customers via email integration, and might save a sale 
When orders are moved from brokering queue to the backorder parking, it does not automatically associate it with a purchase order and set promise date for the order item. Though, the user can manually associate an order item with a PO from the view sales order page.
Upon request, automations can be enabled to associate newly added items in the backorder queue to a purchase order if available. If associated and a promise date is applied, retailers that have the scheduled promise date change feed enabled can will see those recently moved order items in that feed.
This feed can also be used in conjunction with an email platform like Klaviyo to automatically send emails to customers about their new estimated arrival date.
In one of the project implementation job is scheduled daily once that associates sales order in preorder/backorder parking to active PO and update the promise date on the sales order.
Later client notifies customer about the new arrival date via mail and it’s on customer now whether to wait or not for the product.
Hope this helps!