expire date on keys

[Mario Moder]

Hi there!

I studied much information about GnuPG and PGP in general but I've
never found an answer to this question:

I generated a key pair with --gen-key and set an expire date on my
key. The UID is "Mario Moder <moderm@gmx.net>". When I send my public
key to a keyserver or to some persons and the key will expire on the
specified date, what will happen? Do I have to generate a new key
pair? Can I use the same (Mario Moder <moderm@gmx.net>) User ID then
(I don't want to change my email-address)? Or can I simply set a new
expire date and then sent my (old) key (with the new date) to a
keyserver again?

Greetings and thanks,

        Mario