In our privacy notice, we mention the ability for data subjects to contact us if they want to opt out.
However, the more common scenario is that individuals will request the controllers (our clients) to opt out – since the controllers are the ones communicating with these individuals (in theory, the individuals don’t even know we exist, communications to them is done by our clients).
When our clients receive such requests they can cascade this request to us. For that process, we have a policy called “Assistance to Controllers” which details what information a customer will need to provide us in order for us to e.g. remove the person details so they’re not sent to the client.