Sorry, I'm not near my drone, or I'd explain this better. I have not done it myself, but I saw that I could do it.
If you have the latest update, you have to turn "Sport Mode" ON. If you're on the older version of software, it's turn "Easy Mode" OFF.
From there, you should be able to go into preferences (or is it settings...) and change it from 400 to whatever else you like.