There are two ways to unlink a SXSW credential from your SXSW Account. After unlinking, you can log in to social.sxsw.com with your preferred SXSW account and apply the link code you just freed up by unlinking.
Via SXSW Social
First, sign in to social.sxsw.com with the account you wish to unlink. For SXSW EDU, sign in to social.sxswedu.com.
Click the “Unlink this Account” link at the top of the page.
Via the SXSW Schedule
Sign in to schedule.sxsw.com with the account you wish to unlink. For EDU, sign in to schedule.sxswedu.com.
Hover your mouse over your name on the top right of the screen, then select “Unlink A Badge”.