I have a custom report that mostly pulls dates of single owner tasks into columns. But I now have an instance where I need to pull the date a Task Status changed on a task that has multiple people assigned to it. Help!

I have a custom report that mostly pulls dates of single owner tasks into columns. But I now have an instance where I need to pull the date a Task Status changed on a task that has multiple people assigned to it.

I'm having trouble finding any kind of documentation.

Currently I pull certain info out using this formula that was given to me by my WF consultant:

displayname=Concept Route Internally

listdelimiter=<p>

listmethod=nested(tasks).lists

textmode=true

type=iterate

usewidths=true

valueexpression=IF({templateTask}.{name}="Route Concept for Approval",{plannedStartDate})

valueformat=HTML

width=50

But now, I also need to include the date that a Task Status changed and I am stumped. Anyone have any tips, tricks or insights???