I have a workflow on an item and I do certain things when an status column changes.
I need to prevent a user from changing the status to "Witnessed" if they don't fill in the "witnessed person" field. How can I do this? I think that if it was in a workflow, that would be too late, because the item would be changed. Should it be done in an event receiver? Will this mess with my workflow? I need them both running at the same time.