The Luminate Plugin in Raiser's Edge processes both new constituents and transactions as well as updates to either of those things. So contacts for example will sync over as a new update whenever a change is made to their record in Luminate, not just when they initially migrate to Raiser's Edge. This is the same for transactions, if a transaction changes it will show up as a new plugin update to synchronize those changes. Some examples of when this would happen are if the transaction moved to another record (like with a duplicate merge) or a new receipt was issued.