Unsubscribing from follow up comments

In the .(JavaScript must be enabled to view this email address), I can have a checkbox that allows me to tell EE to notify me of follow up comments.

{exp:comment:form channel="news" preview="channel/preview"}
    ...
    <textarea name="comment" cols="70" rows="10">{comment}</textarea>
    ...
    <label><input type="checkbox" name="notify_me" value="yes" {notify_me} /> Notify me of follow-up comments?</label>

    ...
{/exp:comment:form}

I want the users to be able to toggle this feature since some of them want this feature disabled.

So I tried a solution. I unchecked the checkbox and submit with a blank comment textarea field.

However, when doing that I am shown an EE error that tells me that the comment field should not be blank.

My question is, how do I unsubscribe?