You can update the name on your Fatsoma account anytime in your account settings.
What about the name on my tickets?
Once your tickets have been issued, we're unable to update the name printed on the PDF. The good news is that most events don't require the name on your ticket to match the ID you use to get in, so this usually isn't something to worry about.
If you're attending an event that does require the names to match, you'll need to contact the event organiser directly. They'll be able to let you know what your options are.