ORA-30082: datetime/interval column to be modified

Is there any way to resolve the below ORA-30082 error.

SQL> select * from t2_date;

EFF_DT1
---------------------------------------------------------------------------
JOIN_DT
---------------------------------------------------------------------------
03-FEB-16 09.30.05.422 PM
03-FEB-16 09.30.05.421689 PM

SQL> alter table t2_date modify Join_dt timestamp(3);
alter table t2_date modify Join_dt timestamp(3)
                           *
ERROR at line 1:
ORA-30082: datetime/interval column to be modified must be empty to decrease
fractional second or leading field precision
.