Excellent question!  

To change your password, you'll need to delete the app and reload from the respective app store.  When you are prompted to login you can click or tap on the Forgot Password option.  After entering your email address, this will send you a link to reset your password and you can log in with the new one.   After the password is changed, it is very important that you remove the Vipor app from all other devices and reinstall as well so they can be "aware" of the password change.   

For iOS this is as simple as deleting the app on your iPhone or iPad and downloading again from the iTunes App Store.  On Mac, you do not need to delete the Vipor app , but you DO have to remove the data.  We have detailed steps listed in this article along with screen shots:

How to delete all Vipor data on your Mac to start fresh