Expired Subkey - How to extend expiry using GPG command line

[gpg.20.subu at spamgourmet.com]

Hi


I have a key where the sub key has expired

Is there a way to extend the validity of the *sub key* using GPG command
line interface

p.s. - As of now I am little hesitant to set up GPG shell etc - learn
these and then do the sub key edit - so would prefer a straight sub -
key editing

Thanks in adv

-- Subu