how can I change my username?

I need to change my user name from werunvr to raceplorer

As per your request, I changed your username to raceplor.

If you have any forms with custom URL links, you will need to re-create the URL with the new username as the old link will not be active. However, direct links will work fine.

Guide: How-to-Create-a-Custom-URL-of-a-Form