On hand is not reduced from available inventory

The business has export sales, at the time of creating the sales order there isn not on hand since by strategy products are sold based on the forecast, a personalized orchestration process skip the reserve step was created to allow the creation and sending of the requested from WMS but we are faced with the problem that the on hand is not reduced.When the WMS dispatch confirmation is received, the inventory reduction is not made, we also try to create a manual reservation with the document number of the sales order, however, when it is dispatched, the reserve is not