How to add authentication capabilities to an existing key?

[Paul R. Ramer]

Anthony Papillion <anthony at cajuntechie.org> wrote:
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>Is there a good way to add authentication capabilities to an existing
>RSA key? I see how to toggle it if I create a new subkey but not how
>to add it to an existing key.
[snip]

Hello Anthony,

As far as I know, there is no such capability to do that with gpg.  You have to set that capability when you create the key.  HTH.

Cheers,

--Paul