Deconfigure Enterprise Manager Database Control in 11g

We can deconfigure Enterprise Manager Database Control using below command.

Syntax:
emca -deconfig dbcontrol db -repos drop -SYS_PWD -SYSMAN_PWD


Eg:
$ emca -deconfig dbcontrol db -repos drop -SYS_PWD sys123 -SYSMAN_PWD sys123


STARTED EMCA at Feb 28, 2012 3:11:53 AM
EM Configuration Assistant, Version 11.2.0.0.2 Production
Copyright (c) 2003, 2005, Oracle.  All rights reserved.

Enter the following information:
Database SID: omsdb12c
Listener port number: 1521

Do you wish to continue? [yes(Y)/no(N)]: y
Feb 28, 2012 3:12:06 AM oracle.sysman.emcp.EMConfig perform
INFO: This operation is being logged at /orasw/app/oracle/cfgtoollogs/emca/omsdb12c/emca_2012_02_28_03_11_52.log.
Feb 28, 2012 3:12:06 AM oracle.sysman.emcp.util.DBControlUtil stopOMS
INFO: Stopping Database Control (this may take a while) ...
Feb 28, 2012 3:12:26 AM oracle.sysman.emcp.EMReposConfig invoke
INFO: Dropping the EM repository (this may take a while) ...
Feb 28, 2012 3:13:30 AM oracle.sysman.emcp.EMReposConfig invoke
INFO: Repository successfully dropped
Enterprise Manager configuration completed successfully
FINISHED EMCA at Feb 28, 2012 3:13:32 AM