If you have a really good reason for having your username changed, then why not try a /msg gods? There are few reasons for requiring a new username. Note the word requiring. Wanting a new username isn't a good enough reason. If you want a new username, simply register a new one. Many people here have done that and it seems to work quite well. Besides, how many sites actually let you change your handle on the fly?
(Oh, as for problems with changing links to reflect new usernames, there is a database table somewhere that allows mapping of a keyword to a node id. I forget the table name. It contains the word 'keyword' anyhow.)
If the above content is missing any vital points or you feel that any of the information is misleading, incorrect or irrelevant, please feel free to downvote the post. At the same time, please reply to this node or /msg me to inform me as to what is wrong with the post, so that I may update the node to the best of my ability.