replacement

For the Modify action, indicates whether CloudFormation will replace the resource by creating a new one and deleting the old one. This value depends on the value of the RequiresRecreation property in the ResourceTargetDefinition structure. For example, if the RequiresRecreation field is Always and the Evaluation field is Static, Replacement is True. If the RequiresRecreation field is Always and the Evaluation field is Dynamic, Replacement is Conditional.

If you have multiple changes with different RequiresRecreation values, the Replacement value depends on the change with the most impact. A RequiresRecreation value of Always has the most impact, followed by Conditional, and then Never.