One of the main changes in instigating a system of quality management to meet ISO standards is the introduction of traceability. All changes to QMS documentation, paticularly to procedures, should be documented. At the bottom of the Quality Manual and all procedures there should be a Document History. The History should consist of the issue number (which takes the next sequential number each time a change is made) the reason for the re-issue and the name of the person who approved the re-issue.
Before any changes are made to QMS documentation a copy should be placed in a file archive so that there is an audit trail.