DELETE VARIABLES
DELETE VARIABLES deletes the specified variables from the dictionary.
DELETE VARIABLES VAR_LIST.
DELETE VARIABLES should not be used after defining transformations
but before executing a procedure. If it is anyhow, it causes the data
to be read. If it is used while TEMPORARY is in effect, it causes
the temporary transformations to become permanent.
DELETE VARIABLES may not be used to delete all variables from the
dictionary; use NEW FILE instead.