Updating customer data


Hi i have question regarding above
I want to add another subsription form but i want to have possibility to add new subsriber email to a list or update custom fields of current subsriber, is there any chance to achieve it?
But when someone want to subscribe again there is info that email is already subscribed to the list
I remember we implemented a way so that when an existing subscriber tries to subscribe again in the same list he is part of, he is redirected to the update-profile page for doing an update instead.
Here's what it says in my test:
Screenshot 2017-06-28 16.42.38.png