I have an online list that has a lots of columns. Columns A,B,C and D are in date format. Date in column D is always populated, but dates that are in A, B and C should be entered later on, before the date in D. I need a workflow that sends out an e-mail if dates are in A, B and C are not populated two weeks before the date in D. If any of columns of A, B and C are empty e-mail should let person know that date in D is approaching. I use SharePoint 365. Thank you in advance.