I have databases on NT server , 8 on one machine, all with
REMOTE_LOGIN_PASSWORDFILE=SHARED. I want to change to REMOTE_LOGIN_PASSWORDFILE=EXCLUSIVE for each one, so I can log in as SYS with SYSDBA rights.

Do I need to take all the databases down, ie at the same time
and then change all of the init.ora's and then bring them all back up again OR can each one be done in turn without harm??