Hi,
Yes, you can use SWUE to start a new instance of the workflow. It will (of course) start from the very beginning again.
You need to consider if the user_id of the 'workflow initiator' is important to the logic of the workflow. You don't want, for example, a leave approval workflow going to YOUR supervisor.
Of course, if you haven't fixed the problem with the original workflow, it will probably happen again!
good luck
Paul