The same way you changed the sockpuppet name in the heading of the story. Log in as the sockpuppet, go into the story, click on the "edit" icon near the top, then scroll down until you see the tags list. Edit the sockpuppet name listed there for the "remix author" to your own, save the change and voila! You're done. Revel in the knowledge that all searching for your very nice Buffy/Giles story under your name on the tags list will not be frustrated. ;-)
Re: Nice Work
The same way you changed the sockpuppet name in the heading of the story. Log in as the sockpuppet, go into the story, click on the "edit" icon near the top, then scroll down until you see the tags list. Edit the sockpuppet name listed there for the "remix author" to your own, save the change and voila! You're done. Revel in the knowledge that all searching for your very nice Buffy/Giles story under your name on the tags list will not be frustrated. ;-)