Chante domain type - Postgres 9.2

[Patrick B <patrickbakerbr@xxxxxxxxx>]

Hi guys,

I've got this domain: 

CREATE DOMAIN public.a_city
  AS character varying(80)
  COLLATE pg_catalog."default";

And I need to increase the type from character varying(80) to character varying(255).

How can I do that? didn't find info about it. I'm using Postgres 9.2

Thanks!

Patrick