How to change the connection string of the Oracle Enterprise Manager Grid Control 11g repository

If you moved your repository to a new host and want to change the connection string, no need to drop it, no need to messup in the properties or xml files, simply read the doc

http://download.oracle.com/docs/cd/E11857_01/em.111/e16790/ha_agent.htm#autoId13
emctl config oms -store_repos_details (-repos_host -repos_port -repos_sid | -repos_conndesc ) -repos_user [-repos_pwd ] [-no_check_db]

Yes it works!