Unfortunately, changing your Stack e-mail is not yet possible.
We will be adding that option in the Profile settings menu soon.
And that will allow you to do it manually.
However, if due to some reasons changing the e-mail is an urgent necessity, please write to us in the live chat and our development team will assist you in this process.
P.s. The information given above may be irrelevant or outdated. We will be updating the page soon. Sorry for the inconvenience and thank you for your patience!