How to Remove 12c EM Express
SQL> exec DBMS_XDB_CONFIG.sethttpsport(0);
or
SQL> exec DBMS_XDB_CONFIG.sethttpsport(null);
But this Functionality currently is not working Due to Bug 17535882 : DBMS_XDB_CONFIG.SETHTTPSPORT(0): ORA-30952: ILLEGAL CONFIGURATION OF HTTP/HTTPS ,
Which was closed as Duplicate of unpublished Bug 17213197 : ORA-44718: PORT CONFLICT IN XDB CONFIGURATION FILE LEADS TO INSTANCE CRASH
which will be Fixed in 12.1.0.2.0 Patchset and 12.2 Base Release.
Please Apply Patch 17213197 if available or upgrade to the Patchset where Bug 17213197 is fixed .
or You can use any of the following workarounds to unset the HTTPS port :
1- Remove The <sid>XDB Dispatcher setting :
SQL> alter system set dispatchers='';
System altered.
SQL> select name from V$DISPATCHER;
NAME
----
D000
SQL> ALTER SYSTEM SHUTDOWN 'D000';
System altered.
The Dispatcher stops accepting new connections and will wait until all of the sessions it handles are disconnected before shutting down.
SQL> ALTER SYSTEM SHUTDOWN IMMEDIATE 'D000';
System altered.
The IMMEDIATE keyword stops the Dispatcher from accepting new connections and immediately terminates all existing connections through that Dispatcher. After all sessions are cleaned up, the Dispatcher process shuts down.
System altered.
SQL> select name from V$DISPATCHER;
NAME
----
D000
SQL> ALTER SYSTEM SHUTDOWN 'D000';
System altered.
The Dispatcher stops accepting new connections and will wait until all of the sessions it handles are disconnected before shutting down.
SQL> ALTER SYSTEM SHUTDOWN IMMEDIATE 'D000';
System altered.
The IMMEDIATE keyword stops the Dispatcher from accepting new connections and immediately terminates all existing connections through that Dispatcher. After all sessions are cleaned up, the Dispatcher process shuts down.
2- Block the Current used Port from the OS level
.