What is the best way to handle in-process work when instructions change?

The best way is to treat in-process work as a controlled disposition problem, not just a document update. Do not silently replace instructions for work already in progress. Identify the affected lots, serial numbers, work orders, or travelers; determine revision effectivity; and decide whether each unit continues under the old revision, transitions to the new revision at a defined operation, is held, inspected, reworked, or dispositioned through quality processes.

The right answer depends on the nature of the change. A typo or clarification may only require controlled communication and record retention. A change to sequence, tooling, inspection criteria, torque values, material handling, acceptance criteria, or customer-controlled requirements may require engineering review, quality approval, supplemental inspection, rework instructions, customer notification, or formal deviation handling. Those requirements are site-, product-, customer-, and regulatorily driven.

Common control points

• Freeze or flag affected WIP. Prevent operators from unknowingly working to the wrong revision while the impact is assessed.
• Define effectivity clearly. Use a date, time, work order, serial range, lot, operation step, or configuration break that can be audited later.
• Perform a WIP impact assessment. Determine which steps are complete, which records were created, what material state exists, and whether completed work still conforms.
• Disposition WIP explicitly. Document whether work continues as-is, transitions at a defined step, receives added inspection, requires rework, or must be placed on hold.
• Preserve the execution record. The record should show which instruction revision was used for each operation, not just the latest approved revision.
• Communicate and train where needed. If the change affects how work is performed, operator acknowledgement or retraining may be necessary before release.

How this usually interacts with systems

In a controlled environment, PLM or document control is often the source of approved engineering or instruction revisions. MES or a digital traveler controls execution at the operation level. ERP may hold work orders, routings, inventory status, and cost impacts. QMS may manage deviations, nonconformances, CAPA, training records, and approval workflows.

These systems rarely align perfectly in brownfield plants. If revision effectivity is not mapped consistently between PLM, MES, ERP, and QMS, the plant may need temporary manual holds, controlled workarounds, or quality gates. That is not ideal, but it is often safer than allowing uncontrolled revision mixing. Full replacement of legacy systems is usually unrealistic in regulated manufacturing because of validation cost, qualification burden, downtime risk, integration complexity, and long equipment lifecycles.

Common failure modes

• Updating digital instructions without preserving what active work actually used.
• Allowing paper copies, screenshots, or local files to remain in circulation after a change.
• Changing the instruction but not the routing, inspection plan, tooling requirement, or training requirement.
• Assuming all WIP can move to the new revision without checking completed operations.
• Creating mixed-revision product records that cannot be explained during customer review or audit.

The practical rule is simple: separate the release of the new instruction from the disposition of work already underway. The new revision may be valid going forward, but active WIP needs its own documented decision path.