When a part revision is released, the document survey is locked and a new snapshot of the part's characteristics will be created. If you approve an engineering part revision that is not released, a warning is given. The characteristics from the snapshot will be used in reports and calculations if the revision is released; if the revision is not released, the characteristics from Part Catalog will be used. If the part is released, the document survey will be locked for the project item and the engineering part revision. No changes can be done in the document survey after a release, and all data written in the Comp.Spec report (RFQ supplement) cannot be changed after it is approved and sent to sub-suppliers. If changes are needed, a new revision of the part must be created in PDM Configuration, and a Replace Part revision function can be run.