The default owner of database schema is "aedbadmin" as defined through the installation procedure.
Is this also the user defined as the AutoSys database user?
The "DBAccess" parameter in $AUTOUSER/config.$AUTOSERV file allows you to determine whether "aedbadmin" or "autosys" is the user configured for database access.
You will need to use "autosys_secure" option  Change database password in order to modify the database password for the AutoSys database user.
The Scheduler must be stopped during this operation.