"cannot alter to not final since its attribute column is substitutable"
*Cause: An attempt was made to alter a type to not final when its
embedded attribute is defined as substitutable in some tables.
Note, this is a restriction in 9.0 version because when a type is
altered to not final, column of that type is set to not
substitutable at all levels; thus, it is an error if one of its
embedded attribute column is already marked substitutable.
*Action: Recreate the table and specify NOT SUBSTITUTABLE AT ALL LEVELS
for all columns of non final type. Then resubmit the ALTER TYPE