To update the opt-in status of a customer if they requested that, follow the steps below:
Click SCV, then click Search contact.
In the search bar, search for the contact's name or email address.
Click the Display Contact Profile
icon.Click Data Tree
, then by Communications, click the arrow 
icon.By your business name, click the arrow icon then by Optin, click the arrow
icon.By the Email box:
To opt out the customer: un-tick the box by Email. The tick box will look like this
To opt in the customer: tick the box by Email. The tick box will look like this
Go back now to the Summary page and click the refresh
icon.By Contactable, hover over the email icon and verify if it's now set as:
Opted-out: red no
icon.Opted-in: green yes
icon.