A nonconcurrent load isolated update operation on a load isolated table updates the matched rows in-place.
A concurrent load isolated update operation on a load isolated table logically deletes the matched rows and inserts the rows with the modified values. The rows are marked as deleted and the space is not reclaimed until you issue an ALTER TABLE statement with the RELEASE DELETED ROWS option. See Teradata Vantage™ - SQL Data Definition Language Syntax and Examples, B035-1144.