At times one would want to change properties/attributes of a table so new partitions are affected by change not the partitions already created, like example compression, change PCTFREE, default tablespace.

-- enable compression for all operations and change PCTFREE
SQL> ALTER TABLE scott.part_table MODIFY DEFAULT ATTRIBUTES COMPRESS FOR ALL OPERATIONS PCTFREE 5;

-- Change default tablespace for new partitions
SQL> ALTER TABLE scott.part_table MODIFY DEFAULT ATTRIBUTES TABLESPACE NEW_TABLESPACE;

It can be done on partition indexes too.
SQL> ALTER INDEX scott.local_index MODIFY DEFAULT ATTRIBUTES TABLESPACE NEW_TABLESPACE_IDX;