How do I fix a contact connected to the wrong IP?

A client received a Marketo email then forwarded it to their sales person. The sales person then went and clicked on every link in the forwarded email. Marketo now believes that the sales person is the client. They are all over the corporate site and triggering engagement alerts and messing things up. How do I un-ring the bell? I cannot ask the client to fix it by clicking on the correct email. I cannot delete the client. How can this be fixed on the admin side?