A number of good questions have been raised about the building permit application solution that we built. One question in particular that I see frequently relates to the SharePoint columns that were promoted from the InfoPath form template. How did we enable some of those columns to be editable so that they could be modified by a SharePoint Designer workflow?
The answer to the question is actually quite simple. When you publish the form template, the InfoPath Publishing Wizard displays the fields that are to be promoted as SharePoint columns.
If you double-click any of these fields in the Publishing Wizard, the Select a Field or Group dialog box appears and allows you to set the column name and the data source field that is bound to the column. At the bottom of this dialog box is an option to Allow users to edit data in this field by using a datasheet or properties page. Selecting that check box makes the SharePoint column editable, meaning that is can be modified by actions in a SharePoint Designer workflow.
I would have posted about this earlier, but the InfoPath team beat me to it in June, when I had just started a six-part series about the building permit application solution. Incidentally, the InfoPath team refers to this process as "property demotion".