Sometimes people simply don’t see the unsubscribe link at the bottom of the emails. Or they are too lazy to click on it.

Here are some ways to manually unsubscribe a user:

1.From the user profile page

Each email address has a profile page. You can search using its email address., in Users -> Users

Clicking on the email address will display the user profile information. Here you can manually choose to subscribe/unsubscribe an email, setting Is Subscribed to Newsletter and/or Is Subscribed to Transactional emails to FALSE

2. From the shop unsubscribe page

From Setup -> Pages -> Custom Domain&Links you can click the link next to Unsubscribe page: which will get you to your own unsubscribe page.

Here just enter user email address and click unsubscribe. It will be unsubscribed from both newsletter and transactional type of emails.