-- Stop all the OMS:
$OMS_HOME/bin/emctl stop oms
-- Modify the SYSMAN password:
$OMS_HOME/bin/emctl config oms -change_repos_pwd -use_sys_pwd -sys_pwd <sys pwd> -new_pwd <new sysman pwd>
* I got some errors on this command.
In this case I started the OMS in admin only mode and the command worked correctly.
$OMS_HOME/bin/emctl stop oms -admin_only
-- Re-start all the OMS:
$OMS_HOME/bin/emctl stop oms -all
$OMS_HOME/bin/emctl start oms