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If the recipient chooses this option, Seatrobot declines them from the event, marks them as Unsubscribed - Do Not Mail in your Contacts section. Contacts marked 'Unsubscribed - Do Not Mail' cannot be included in any future emails for any event from the organization. This status cannot be undone by the organization.
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Find the unsubscribed contact in Contacts (either by searching for them by name, or by using the Status Filter.
Click on their First Name in the contact row to access their Contact Details page
You will see the contact's Send Status panel has the contact marked as Current Status: Do Not Mail - Unsubscribe. Next to it also is a button to copy a re-subscribe link:
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