To err is human, to recover is DBA

emctl status dbconsole        (without semicolon)
emctl start dbconsole
emctl stop dbconsole

Change DBID in database

shu immediate

startup mount

nid target=/ logfile=change_dbid.log

change_dbid.log

startup mount

alter database open resetlogs;

Change dbname

shu immediate

startup mount

create pfile='D:\app\dbs\initorcl2.ora' from spfile;

nid target=sys/sys123@orcl dbname=orcl2 setname=yes logfile=db_change_name.log

open pfile and change orcl to orcl2

startup pfile='pfile='D:\app\dbs\initorcl2.ora';