You can change your password from the Settings menu in the top right corner of Float by selecting Profile Settings.
If you've forgotten your password and need to request a new one, you can use the "Forgot your password or username?" option at the bottom of the login page.
Note: You cannot reset your password via the mobile app at this time.
You can also reset a person's password from the Access tab within their profile (or by clicking Edit when hovering over a guest's name).