Here is my need. I have a visit date that I want to prepare for 3 weeks in advance. So if I have a date of 5/23/14 for the visit I want a cell to show me the date of 5/2/14 as the prep day. However if the visit date has past, I want the date of the visist to be defaulted in this prep date. So for example if the visit date was 1/23/14 I would want the prep date to be 1/23/14.