We have a document review workflow that has a set list of approvers. In demo'ing the system today, a request was made to allow an Ad-hoc workflow stop. Here was the described scenario:
A review workflow approver gets a review/approval task assigned to them. But before they are willing to approve the document, they want to be able to route someone else to get feedback on it. The actual person it would be assigned to varies based on the contents of the document being reviewed and therefore cannot be accommodated in advance. So what they want is the ability to (optionally) click an "Add Ad-Hoc Reviewer" button that would let them then select a user who have a review task assigned to them that will return it back to the Ad-Hoc Review Requestor before they determine whether to Approve or not and have the workflow move along as pre-built.
Any ideas on how to accomplish this?
you moreless described a proper solution
but you do not need to stop workflow for that at all. it just adds one another approval step/level.
so, add one more possible outcome for the approver like 'Review needed' and add people picker control on task form where he/she could select a reviewer.
when you get that outcome you can in workflow decide you need to route workflow to a state to make a review, which assigns a task to selected reviewer. once the reviewer confirms its task, you route workflow once again to approver branch and assign new task to approver.