InfoPath Dev

That is wonderful!  Thank you, Hilary, both for sharing your knowledge and your time :)

Based on the logic you outlined, I'd actually use 4 rules - I'm attaching a simple sample. Right click the link in the post header, and save the file locally. Right click the saved file and select design - from there you can preview and try it out. :)

 Hi Hilary, thank you for answering my query.   If it's not possible then I think that would be an acceptable solution.  Would I add 3 validation rules to the date picker? 

I don't think you'll be able to restrict their ability to pick a date - however, you could run validation after the date has been entered. Is that acceptable?

 Hi, I hope someone is able to help.   I have a date picker field that I would like to restrict depending on the result of another field.  For example:  I have a choice  field (Priority Rating) with 3 options: P1, P2, P3Depending on which option is selected I would like to affect the date picker (Deferral ...

Hilary, thank you so much. It worked out perfectly for me.

You could use a secondary data source for the values - set up lists in SharePoint with the required values, add data connections to the lists, and use those for the values for the dropdowns / multi-selects. Then give your user permissions to the lists so they can edit the values.

I created a form in InfoPath 2013 and published it in Office 365 SharePoint 2016. How can a user add/delete values in the drop down list box and multiple selection list box of InfoPath form without going to InfoPath design form?

Are you using SharePoint workflow for this?

Unfortunately, I don't think there is any way to do that. I think you'll need to start from scratch - just recreate the rules & controls in a new template part.