I am tasked with figuring out how to automatically reassign tasks in sharepoint 2007 designer workflow. I know that it's usually done by providing the user with a reassign option in the task completion form, but that won't work for me. Here's a brief overview of the current workflow and what I need it to be able to do.

It's actually a primary workflow and a secondary workflow. The primary checks statuses, sends emails and assigns tasks. The secondary updates the status to an appropriate level each time a task is completed. Tasks are assigned based on fields within the primary list. For example their is a PM field. That is populated with a person when a new list item is created. And the workflow assigns a task to that PM.

What I need to happen is that if at any point, someone goes in to the primary list and changes the PM, I need to reassign the applicable tasks to that new without additional user interaction.

I'm not sure how to do this. Any ideas? Thanks much!