You can drop interval partitions in an interval-partitioned table. This operation drops the data for the interval only and leaves the interval definition in tact. If data is inserted in the interval just dropped, then the database again creates an interval partition.
You can also drop range partitions in an interval-partitioned table. The rules for dropping a range partition in an interval-partitioned table follow the rules for dropping a range partition in a range-partitioned table. If you drop a range partition in the middle of a set of range partitions, then the lower boundary for the next range partition shifts to the lower boundary of the range partition you just dropped. You cannot drop the highest range partition in the range-partitioned section of an interval-partitioned table.
The following example drops the September 2007 interval partition from the sales table. There are only local indexes so no indexes are invalidated.
ALTER TABLE sales DROP PARTITION FOR(TO_DATE('01-SEP-2007','dd-MON-yyyy'));