As of now you cannot change your email address of your Proxeuse account yourselves. This is due to the fact that several (internal) applications use your email address as a way to identify you. Changing this value would break your account on one of these applications.
Our customer service team can help you change your email address. Please contact them with the request to have it changed. Include your current and future email address as well as your name and address.
We're working on letting you change your email address yourselves. However, there is currently no ETA on this.