SQL & PL/SQL :: Partition Key Updation Effects On Memory Consumed

if we update partition key, internally row movement is done as if you had in fact deleted the row and reinserted it. It will update every single index on this table, and delete the old entry and insert a new one. It will do the physical work of a DELETE plus an INSERT. However, it is considered an update by Oracle even though it physically deletes and inserts the row¿therefore, it won't cause INSERT and DELETE triggers to fire, just the UPDATE triggers. Additionally, child tables that might prevent a DELETE due to a foreign key constraint won¿t. You do have to be prepared, however, for the extra work that will be performed; it is much more expensive than a normal UPDATE.

CREATE TABLE MYTEST1
(
MYID NUMBER(10) PRIMARY KEY,
MYFLAG VARCHAR2(1)
) TABLESPACE SIMANG_D
PARTITION BY LIST (MYFLAG)
(
PARTITION P1 VALUES ('A') tablespace DJB,
PARTITION P2 VALUES ('B') tablespace users
);
[code]....

In above I inserted few rows into table and those belong to partition P1 and Tablespace DJB and then I updated partition key from A to B which resulted row movement from partition P1 to P2 which belong to tablespace users. Before updation data has consumed some space in tablespace DJB and after update those records consumed some space in tablespace USERS. But in this scenario I checked that space consumed in DJB is not released. Is there any way to get this space released ?