If you have Integration between The Raiser's Edge and the education software, records are added and linked to one another from one database to the other. If a record is added by mistake, it can be deleted. It can be manually deleted from either database, even if they are linked.
If a linked record is deleted from one database, it will not be added back the next time Synchronization runs. The record in the other database will remain intact and Synchronization will remove the Integration ID from the record the next time it is run, which indicates the remaining record is an unlinked record.