Trigger function does not modify the NEW value

I have a trigger that is created like so:

    create trigger tr_on_table_modified after insert or delete or update
        on some_table for each row execute procedure on_table_modified();

    CREATE OR REPLACE FUNCTION on_table_modified() RETURNS trigger LANGUAGE plpgsql $$
        /* some code that does not modify any values but calls PERFORM on another function */
       
        raise notice 'lowercasing %', new.email;
        new.email = lower(new.email);
        raise notice '    to %', new.email;

        return new;
    $$

I can see in the output the notices with the expected values, but the value in the updated record is not lower-cased.

update some_table
set    email = 'IGAL@Lucee.org'
where  id = 1;

> 00000: lowercasing IGAL@Lucee.org
> 00000:     to igal@lucee.org

select email
from   some_table
where  id = 1;

> email         |
> --------------|
> IGAL@Lucee.org|

Any ideas?

Thanks,