Suppose your supplier sends this message after the order is confirmed: “The original component is temporarily unavailable. We can use another one. The function is the same.”
Before replying, find out what “the same” covers. A component may perform the same basic function while differing in ways that matter to your order. The supplier needs to explain the proposed change against the requirements already agreed.
At ESG, we recommend clarifying the change, its supporting evidence and its effect on the order before deciding whether to accept it. A substitution may be workable, but the people reviewing it need more than a verbal assurance.
Establish exactly what is changing
Ask the supplier to put the original requirement and proposed replacement side by side. Identify the material grade, brand, model or specification being changed, with references to the agreed documents. The description should be specific enough for reviewers to know which part of the equipment is affected.
Confirm the purchase order, line item and quantity involved. A proposal affecting a few units should not leave you wondering whether the supplier intends to change the entire order—or future orders as well.
Also establish how far the supplier has proceeded. Is this still a proposal, or has the replacement already been purchased, fitted or used in production?
That status affects the available next steps. If work has already started, ask which units are affected and agree how the affected work will be handled while the proposal is reviewed. Work already completed is not, by itself, a reason to approve the substitution.
Ask for evidence against the agreed requirements
The supplier’s explanation should connect the proposed replacement to the equipment’s actual use. Ask why it recommends the alternative, what differences it has identified and what information supports its assessment.
Keep the request focused. A relevant datasheet, drawing or material record may help answer a specific question; a large folder of general brochures may not. Ask the supplier to point to the information that supports the requirement under review.
For example, suppose a proposed component has the same nominal rating as the original. That comparison answers one question. It does not tell the reviewer whether the other specified requirements have been checked. This is an illustrative example, not a conclusion that any particular components are interchangeable.
A requirement the supplier has not mentioned remains unconfirmed. Ask it to identify outstanding checks and assumptions explicitly, so reviewers can distinguish supported claims from points that still need attention.
Our guide to comparing technical quotations for industrial equipment explains how to assess differences between offers before ordering. Here, the reference point is the configuration already agreed for your order and the specific departure now being proposed.
Confirm who needs to approve the change
Procurement can gather the proposal, identify missing information and coordinate responses. Technical suitability needs review by personnel qualified to assess the affected requirements.
Check the approval arrangements for the order. A customer-specified brand, approved drawing or contractual requirement may mean that another person or organization must review the proposal. Do not assume that the person receiving the supplier’s email has authority to approve every aspect of it.
Make any outstanding conditions clear before sending a decision. If the technical reviewer still needs a drawing or confirmation of an operating condition, communicate that point rather than reducing the response to “acceptable.”
The supplier should be able to understand what has been approved, what remains open and what it may proceed with.
Carry the decision through to the order
Once the proposal is acceptable to the relevant reviewers, check whether it changes the commercial or delivery arrangements. Depending on the substitution, this may include price, lead time, warranty, installation requirements or spare-parts arrangements. Ask the supplier to confirm any effects rather than assuming that every item changes—or that none does.
Record the decision against the exact replacement and supporting document versions. Include the applicable order, items, quantities and any limits on the approval. A brief written confirmation can be sufficient for a straightforward change if it clearly identifies what was accepted.
Avoid an unqualified “OK” in an email thread containing several proposals. Approval of one identified substitution should not be left open to interpretation as permission for other replacements.
Then check which specifications, drawings or order attachments need updating. The purpose is practical: production should build the accepted configuration, inspection should check that configuration, and the receiving team should know what to expect. If only part of the order changes, keep the affected units or batches identifiable in the relevant records.
Our supplier document guide covers document review and revision checks in more detail. For this change, focus on the records that would otherwise describe the old configuration.
A short reply to request the missing information
You can adapt the following reply to the supplier’s proposal.
Subject: Proposed substitution for PO [number]
Hi [Name],
Thanks for letting us know. Please send a brief comparison of the agreed material or component and the proposed replacement, including the differences, your recommendation basis and supporting information.
Please identify the affected order items and quantities, any effect on price or delivery, and whether other agreed requirements would change. Also confirm whether the substitution is still proposed or has already been purchased or used in production.
This will help us arrange the review. Our request for information does not constitute approval of the change.
Thanks,
[Your name]
Discuss the proposal with ESG
If a supplier’s change request is unclear, share the original specification, the proposed replacement and the supplier’s explanation. Contact ESG to discuss what still needs clarification before the decision is made. Technical acceptance should remain with the appropriately qualified reviewer and follow the approval arrangements for your order.
