Dropping default privileges.

I am unable to drop a user.

drop role tim;
ERROR:  role "tim" cannot be dropped because some objects depend on it
DETAIL:  owner of default privileges on new relations belonging to
role tim in schema strongmail

ALTER DEFAULT PRIVILEGES IN SCHEMA strongmail
    REVOKE INSERT, SELECT, UPDATE, DELETE, TRUNCATE, REFERENCES,
TRIGGER ON TABLES
    FROM tim;

drop role tim;
ERROR:  role "tim" cannot be dropped because some objects depend on it
DETAIL:  owner of default privileges on new relations belonging to
role tim in schema strongmail

reassign owned by tim to postgres;

Nothing seems to work.