How to update a client's email when using the MailChimp integration.
Navigate to the Client's case.
Go into the Client Tab.
Click the Contact Details header.
A pop-up window will appear.
Update the email 1 section with the new email address.
Click Save.
Click the dropdown menu next to the case status at the top right.
Select Manage Mailchimp Lists.
Update any necessary selections.
Click Save.
The client's new email address will now be subscribed to those MailChimp Lists.