Extending Expiration Date of an Already-Expired GPG Key

[Bruno Wolff III]

On Sat, Feb 21, 2009 at 11:04:21 -0500,
  Robert L Cochran <cochranb at speakeasy.net> wrote:
> My gpg key expired last month and I didn't notice it till today. I used
> gpg --edit-key to extend the expiration date by a year, then I sent it
> to one of the key servers, subkeys.pgp.net. Is this an acceptable
> practice? Google searches yielded a few comments suggesting that an
> expired key could be revoked and a new key generated. I'm unsure what
> accepted practice is.

What I would expect is that one would create a new key and sign it with
the old one.