Notification Policy Question...

I have a policy that I am trying to enact. Basically it checks to see if the start date on a helpdesk "Project" is starting soon (within such and such days) and it edits the incident changing it from "Planned" to "Open" I also want it to email the assigned worker with a quick message and the title of the incident. I've found the name of the field that I need for the email part: assigned_to_worker_email, but my question is how can I put this in the "To Address:" part of the automated action? Can I do that or does it not accept variables like this? Any ideas? Thanks