To make changes to the author's contribution form, such as the email address, there are a number of steps you need to follow.
In your dashboard, go to abstract handling and click on export.
In the page that then opens, click on the download button under the list of contributions.
An Excel sheet will then automatically be downloaded with all the data of the authors and the associated contributions. In this list, in the account link column, you will find links to the author account. With the right person, right-click on the link so that you can open the hyperlink to the author's account.
Make the adjustments and save them. (note, adjustments to the personal profile are automatically saved).
Tip
It works the same for a reviewers account, only you have to export the list of reviewers.