All in all it seems like a sloppy way for Marketo to have you create this... unless you truly don't care about the contact details and history of the first person who was the incorrect contact.
What might work better is: custom answer 1, 2, and 3 fields which you could put onto a Forms 2.0 form as Name:, Email:, Phone: (as examples), then when that form is submitted, send an alert to the appropriate person with the original contact's details, as well as their values for custom answers 1, 2, and 3. The bonus here is that you don't lose the original person's activity, history, or misappropriate it to the new contact. Later, if it's appropriate, a new record could be created manually. Again, not sure how many of these form fills we're talking about.