See this:
http://jamiemonserrate.wordpress.com/2010/01/11/how-to-change-username-and-password-in-git-svn/
Cite as:
Saad, T. "How to change username and password in git-svn?".
Weblog entry from
Please Make A Note.
http://pleasemakeanote.blogspot.com/2013/06/how-to-change-username-and-password-in.html