Once the engineering change order (ECO) has been through all the necessary reviews and received approval by all stakeholders, the change can be implemented. Some companies use an engineering change notice (ECN) to authorize the implementation. Others use the ECO to authorize and and implement the changes. Depending on the nature and urgency of the change—purchasing, manufacturing, and/or supply chain teams may need to take actions ensuring the ECO is acted upon by the targeted date. Parts or subassemblies may need to be sourced and received into inventory. Changes to product processes, standard operating procedures (SOPs), work instructions, and/or manufacturing routings may need to occur. Ultimately, changes to products will be made on the factor floor during production and/or possibly in the field if the disposition of the change requires rework in the field.