Crystal Reports 10 if statement with date & string

I am totally new to Crystal, I've only worked on SSRS. I have a simple if statement, but I'm getting an error because I'm trying to combine a date and a string, all I need is that if date1 < date2 then date1 else don't display anything. I've got the following formula, but Crystal gives an error: "A date is required here" and then highlights the "" after else, how do I go about this?

if {@formatExpDate}  < {@new date} then {@formatExpDate} else ""