Hmm... As I'm understanding this, it's going to be a two-step process and involve a bit of on-page scripting. You'll need an experienced JavaScript/jQuery person to pull this off.
I'm going to assume it's not a risk to your business to pass the PID in the open via URL parameter.
1) In the email "Confirm Your Information" button, add a URL parameter to the link, e.g. http://yourcompany.com/page.html?id={{lead.PID Token}}
I'm not sure what the PID token is called in your database, but that's the basic idea.
2) Add some JavaScript / jQuery to the page where the form is hosted to pull the URL parameter into a hidden ID field
Alternatively, it sounds like you may be wanting to use the PID to reference your CRM and grab data to pre-fill the form? You would use a similar implementation for step 1, but Step 2 would become a bit more complicated and involve some sort of API calls into that system to retrieve the info and pre-fill the forms.