SQL & PL/SQL :: Add Partition To Table Without Partition?

I am trying to add partition to table without partition

with following code

ALTER TABLE ACC_LOC1_TAB
ADD PARTITION testpart BY RANGE (ALT_AUTHDT)
(PARTITION UPTO_2010 values less than (31-mar-2010),
PARTITION APR_JUN_10 VALUES less than (30-JUN-2010),
PARTITION JUL_SEP_10 VALUES less than (30-SEP-2010),
PARTITION OCT_DEC_10 VALUES less than (31-DEC-2010),
PARTITION JAN_MAR_11 VALUES less than (31-MAR-2011))

it will raise error ora-14020