Rename enum item in PostgreSQL

I would like to change the name of an item in an enum type in PostgreSQL 9.1.5.

Here is the type's create stmt:

CREATE TYPE import_action AS ENUM
('Ignored',
'Inserted',
'Updated',
'Task created');

I just want to change 'Task created' to 'Aborted'. It seems like from the documentation, that the following should work:

ALTER TYPE import_action
RENAME ATTRIBUTE "Task created" TO "Aborted"; 

However, I get a msg:

********** Error **********

ERROR: relation "import_action" does not exist
SQL state: 42P01

But, it clearly does exist.

The type is currently being used by more than one table.

I'm being to think that there must not be a way to do this. I've tried the dialog for the type in pgAdminIII, but there is no way that I can see to rename the it there. (So, either a strong hint that I can't do it, or - I'm hoping - a small oversight be the developer that created that dialog)

If I can't do this in one statment? Then what do I need to do? Will I have to write a script to add the item, update all of the records to new value, then drop the old item? Will that even work?

It's seems like this should be a simple thing. As I understand it, the records are just storing a reference to the type and item. I don't think they are actually store the text value that I have given it. But, maybe I'm wrong here as well.

In PostgreSQL version 10, the ability to rename the labels of an enum has been added as part of the ALTER TYPE syntax:

ALTER TYPE name RENAME VALUE 'existing_enum_value' TO 'new_enum_value'

Update: For PostgreSQL version 10 or later, see the top-voted answer.

Names of enum values are called labels, attributes are something different entirely.

Unfortunately changing enum labels is not simple, you have to muck with the system catalog: http://www.postgresql.org/docs/9.1/static/catalog-pg-enum.html

UPDATE pg_enum SET enumlabel = 'Aborted' 
WHERE enumlabel = 'Task created' AND enumtypid = (
  SELECT oid FROM pg_type WHERE typname = 'import_action'
)

The query in the accepted answer doesn't take into account schema names. Here's a safer (and simpler) one, based on http://tech.valgog.com/2010/08/alter-enum-in-postgresql.html

UPDATE pg_catalog.pg_enum
SET enumlabel = 'NEW_LABEL'
WHERE enumtypid = 'SCHEMA_NAME.ENUM_NAME'::regtype::oid AND enumlabel = 'OLD_LABEL'
RETURNING enumlabel;

Note that this requires the "rolcatupdate" (Update catalog directly) permission - even being a superuser is not enough.

It seems that updating the catalog directly is still the only way as of PostgreSQL 9.3.

There's a difference between types, attributes, and values. You can create an enum like this.

CREATE TYPE import_action AS ENUM
('Ignored',
'Inserted',
'Updated',
'Task created');

Having done that, you can add values to the enum.

ALTER TYPE import_action 
ADD VALUE 'Aborted';

But the syntax diagram doesn't show any support for dropping or renaming a value. The syntax you were looking at was the syntax for renaming an attribute, not a value.

Although this design is perhaps surprising, it's also deliberate. From the pgsql-hackers mailing list.

> If you need to modify the values used or want to know what the integer > is, use a lookup table instead. Enums are the wrong abstraction for > you.