Regarding with your question about how to remove the email, In order to remove email from system you can access to Selection data > BRANCH > Click on tab email and double click on the list of email that to would like to in-active.
Please be inform that if you have in-active this email list so this cause will be effect to all email notification that system send to this person eg. Credit-limit Notification Email, Hotel Booking Email, Thanks you Email etc.