reconfig DB Console HTTP port number

cat $ORACLE_HOME/install/portlist.ini

with the arguments to configure DB Control and Agent Port number

emca -reconfig ports -DBCONTROL_HTTP_PORT 5504 -AGENT_PORT 1834

STARTED EMCA at May 12, 2008 2:08:16 PM
EM Configuration Assistant, Version 10.2.0.1.0 Production
Copyright (c) 2003, 2005, Oracle. All rights reserved.

Enter the following information:
Database SID: MNPP

Do you wish to continue? [yes(Y)/no(N)]: Y
May 12, 2008 2:08:24 PM oracle.sysman.emcp.EMConfig perform
INFO: This operation is being logged at /software/oramnp/product/10.2.0/cfgtoollogs/emca/MNPP/emca_2008-05-12_02-08-16-PM.log.
May 12, 2008 2:08:24 PM oracle.sysman.emcp.util.DBControlUtil stopOMS
INFO: Stopping Database Control (this may take a while) ...
May 12, 2008 2:08:38 PM oracle.sysman.emcp.util.DBControlUtil startOMS
INFO: Starting Database Control (this may take a while) ...
May 12, 2008 2:10:20 PM oracle.sysman.emcp.EMDBPostConfig performReconfiguration
INFO: >>>>>>>>>>> The Database Control URL is http://mnp:5504/em <<<<<<<<<<<
Enterprise Manager configuration completed successfully
FINISHED EMCA at May 12, 2008 2:10:20 PM