I am having the same issue... Did you happen to find the solution?
Yes i found the solution. We cannot edit the email id like that from subscriptions page. You can change the email ID by the following option.
Login to Admin Page > Click on "Users" >> Select the User Name/ User ID for which you want to edit >> Now you will be taken to another page where you can update the Email ID to which you want to subscribe.
you can also do this by selecting "User Preferences" menu from the top right corner.
Hope this helps you.