DELETE VARIABLES var_list.
DELETE VARIABLES deletes the specified variables from the dictionary. It may not be used to delete all variables from the dictionary; use NEW FILE to do that (see NEW FILE).
DELETE VARIABLES should not used after defining transformations and before executing a procedure. If it is used in such a context, it causes the data to be read. If it is used while TEMPORARY is in effect, it causes the temporary transformations to become permanent.