Change File name during blob to OS file

When blob was read and written on OS driver by an Oracle PL/SQL procedure, how can I keep file name as it on my_DOCU.NAME or change file name on OS?

All my files were uploaded from an Oracle PL/SQL  web application and saved onto DB table.

SQL> desc my_DOCU;
 Name                                      Null?    Type
 ----------------------------------------- -------- --------------
 NAME                                      NOT NULL VARCHAR2(256)
 MIME_TYPE                                          VARCHAR2(128)
 DOC_SIZE                                           NUMBER
 DAD_CHARSET                                        VARCHAR2(128)
 LAST_UPDATED                                       DATE
 CONTENT_TYPE                                       VARCHAR2(128)
 CONTENT                                            LONG RAW
 BLOB_CONTENT                                       BLOB

File name would be changed during uploading. For instance, irt_rcu.zip would be F2897/irt_rcu.zip.