ECO (engineering change order)
An ECO (engineering change order) is the formal document that authorizes a change to a part's design, specification, or revision. It triggers downstream updates across drawings, the BOM, suppliers, and (often) the open POs that were already in flight on the previous revision.
Part of the Procurement Glossary
How it works in practice
Engineering or quality identifies a needed change to a part: a tolerance tightens, a material substitutes, a feature is added or removed, a revision letter advances. The ECO walks through the company's change-control process (review, approval, sign-off), gets released, and the new revision becomes the version of record. The drawing changes, the BOM changes, and any in-flight POs against the old revision are now in question.
For the buyer, the immediate move when an ECO drops is to check which open POs are affected. For each one: is the supplier already cutting to the old revision, has the part shipped, has it been received, has it been used? The answer determines the next action. A part not yet started can switch revisions cleanly. A part already in production may need to be rejected and re-cut. A part already received and consumed has to be tracked separately for traceability.
A senior buyer learns to ask the supplier the right question fast: "what stage is PO 12345 at, and can it pivot to revision B?" The faster that conversation happens, the more options exist. Waiting a week to call the supplier means the part is probably already cut to the old revision and the recovery is more expensive.
Why it matters
A missed ECO impact on an open PO is a quiet failure. The supplier delivers parts that meet the previous revision and (technically) the original PO; the buyer accepts them; production tries to use them and discovers they no longer match the assembly. By that point the cost is split across scrap, rework, and a delayed build, and nobody is sure where the breakdown happened.
The buyer is not the owner of the ECO process, but the buyer is often the only person watching the open-PO list against the change. Engineering knows the part changed; quality knows the part changed; the supplier may not know unless the buyer tells them, and the impact on schedule shows up in the buyer's firefighting queue first.
Tips
Triage open POs the day the ECO drops
Pull the list of open POs on the affected part as soon as the ECO releases. The cost of recovery scales with how long parts sit in production at the old revision while no one calls the supplier.
Ask one question first: what stage is the part at
Before you debate scrap-versus-rework, find out where each open PO actually is. Not yet started, in setup, on the machine, packed, shipped, or delivered. The recovery option set depends on the answer.
Document the call with the supplier
A revision change that hits an open PO is a commercial conversation. Get the new agreement (revision, ship date, any cost adjustment) in writing in the email thread, even if you also confirm by phone. Verbal-only revisions are how parts ship to the wrong rev.
How PO-Relay helps
PO-Relay does not run the ECO process and does not integrate with PLM systems. The change itself, the approval workflow, and the BOM updates live in engineering and quality's tools (Arena, PTC, Siemens, or whatever the company uses). What PO-Relay does see is the email layer: when a supplier responds to an ECO communication, when they confirm they can pivot, when they ask a clarification question, or when they go silent.
Email Intelligence catches the supplier's response and matches it to the affected open PO. Open Loop Tracking keeps the loop visible until the revision change is acknowledged and the new ship date is confirmed. Auto Follow-Ups drafts the chase email if a supplier has not responded to an ECO-impact question within the response window. The buyer still owns the decision to scrap, rework, or accept; PO-Relay's contribution is making sure the conversations stay tracked alongside the affected POs.