If you want to change your Rave Password while logged into Rave Build, you can do so by clicking on the profile dropdown to the top right of your screen. Then under Profile Settings click on 'Change Password'
From here you just simply enter your current password followed by your new password, then click 'Change Password'
If you have forgotten your Rave Password you will need to check our FAQ for resetting your password while logged out of Rave here I forgot my password, how do I reset it? .