When registering on Stanford Lagunita at lagunita.stanford.edu/register, you were asked to create a custom username for yourself. After creating your account, you cannot change your username yourself. In addition, no other person can have the same username.
Your unique username displays on your dashboard, in exported grade reports that the instructor runs, and in discussions you post or respond to.
If you need to change your username, please contact the platform support team by clicking on the Help tab that displays on the top right side of the screen. The Help link takes you to the Help Center which is where you can submit a request to us. You can also submit a request by going to https://stanfordonline.zendesk.com/hc/en-us/requests/new.