You find your registered email address under Progress -> Profile -> Settings -> Account Settings in the app.
If you log into your account via your web browser you are able to change your connected email yourself, please follow this link
Otherwise, in order to change it, please contact support with information about: 
  1. The current email address.
  2. What address you would like to change to.

You can reach us by following this link and we will be happy to help you with this.