Evidence must still support the claim. Discuss legitimate confidentiality needs and what the process requires with the responsible organization and adviser.
Avoid destroying the explanation
Identify what a redaction would hide and how the remaining evidence establishes the employee’s knowledge. Do not fabricate an unrestricted version of an actual customer project.
Contemporaneous internal records: configuration and revision histories, design documents, authored training material, project files, adaptation records for equipment, and any registered intellectual property. By documenting the company's own systems and the specialist's role in them: internal training records, authorship of procedures, escalation histories, and a statement of how many employees hold comparable knowledge and how long training a replacement would take. Describe the knowledge at the level of function and history rather than formula, and support it with document indexes, redacted excerpts, training logs and declarations from supervisors who can be contacted. Ask supervisors and the employee to reconstruct training history and concrete examples if formal records are incomplete, and be honest about any gaps rather than inventing a paper trail after the fact. Customer names, personal data, and unrelated commercial terms may often be removed, but dates, technical context, authorship, and the applicant’s contribution must remain intelligible. Training records and course outlines answer the first; project files, sign-offs and correspondence answer the second; an internal certification, an escalation list or a role definition answers the third.