Alter - Subpartition a partitioned table

Question

I have a table which is partitioned by RANGE on DATE key

CREATE TABLE T1
  DOC_ID VARCHAR NOT NULL.
  STATE VARCHAR ...
  DOC_DATE
  ...
PARTITION BY RANGE (DOC_DATE)(
PARTITION feb16 VALUES LESS THAN (TO_DATE('01-MAR-2016','DD-MON-YYYY')),
PARTITION mar16 VALUES LESS THAN (TO_DATE('01-APR-2016','DD-MON-YYYY'))
);

There is a need to subpartition on State key, allowing different states data to be inserted accordingly.

How do I Alter my table?

Answer 1

Since I was creating a table with partitions anyhow; I thought it would be good idea to just drop the table and reacreate (//doesn't have any data now)