**To modify a DB instance** The following ``modify-db-instance`` example changes the instance class of the specified running DB instance. The ``--apply-immediately`` parameter causes the DB engine to be replaced immediately, instead of waiting until the next maintenance window. :: aws rds modify-db-instance \ --db-instance-identifier test-instance \ --db-instance-class db.m1.large \ --apply-immediately Output:: { "DBInstance": { "DBInstanceIdentifier": "test-instance", "DBInstanceClass": "db.m1.small", "Engine": "mysql", "DBInstanceStatus": "modifying", <...output omitted...> "PendingModifiedValues": { "DBInstanceClass": "db.m1.large" } <...some output omitted...> } }