To remove a certain recipient from your tracked data, you add the IP-address of the recipient to your IP-blacklist. You can access and manage your IP-blacklist from the IP-blacklist tab on your My Account page. All IP-addresses that you add here will be excluded from your tracked data.
If you disable IP-address tracking, then the IP-blacklist will have no effect.
You can blacklist IP-addresses also directly from the "Raw data" panel. Expand the data row and press the "Blacklist IP" button. Afterwards you need to refresh the page to see the changes. If you need to know which IP-address belongs to which recipients, you can use custom data to tag your recipients.