I'm ready to bet that there are some seasoned posters here that knew this. I've never broken a socket pin off but I'm pretty handy and I might have figured it out looking at how the socket pins are assembled into the unit. But maybe not and I didn't know the procedure before now. So here's another And...
Since you're a yanker (I am too sometimes) and already wondered when this would happen it's probably a good idea to save the sacrificial socket so you can rape it for more pins as needed. Or, better yet, remove the pins from it now, stow them away and toss the socket. That way you can't confuse it for a whole socket at some point when you're taking inventory for a build or repair only to find yourself caught short later.
EDIT: It occurred to me that I actually did ruin a socket pin once. I wasn't over soldering or getting solder down to the base of the pin or anything, but somehow the hot solder wicked into the tube pin hole. I only discovered it when I tried to plug a tube in. I did replace that socket without even considering replacing the pin. So now I'll know better.