Clause 8 Operation
8.5.6 Control of Changes
The organization shall review and control changes for production or service provision, to the extent necessary to ensure continuing conformity with requirements.
The organization shall retain documented information describing the results of the review of changes, the person(s) authorizing the change, and any necessary actions arising from the review.
Refer to clause 6.3, where planning of changes is discussed in detail. At clause 8.5.6, we are looking at changes during the production and delivery of products and services, whether planned or not.
This is another new requirement, introduced in the 2015 version of ISO 9001. It if for the organization to implement a process for responding to unplanned changes that are considered necessary to ensure that products and services continually meet specified requirements.
Changes can occur in any production environment arising from corrective action, design specifications, etc.
An organization is expected to manage this aspect formally to ensure conformance.