Definition
A change order is the audit trail for any deviation from accepted scope after the job is in production. It captures what changed, why, the price delta (positive or negative), the schedule impact and an authorising signature. Standard contract suites all require variations in writing: AIA A201 Article 7 (Change Order, Construction Change Directive, Minor Change), JCT clauses 3 and 5, NEC4 Clause 60 (Compensation Event with an 8-week notification window), FIDIC Clause 13 (Variations and Adjustments).
Example
Why it matters
The biggest source of unrecovered margin in custom-fabrication work is unbilled scope change — verbal upgrades that get done but never invoiced. Every standard form anticipates this and codifies a discipline against it: changes captured formally and immediately, before they are implemented, with cost and time documented and authorised. Verbal-only changes risk losing the contractual entitlement to recover the cost.