I am working on a spreadsheet that has a column where people will enter in
the date they completed a class, then the next column has a formula in it to
show them when they need to take the class again (Every 2 -3 years). If the
completed column is blank, then I need the due next column blank, as well.
But, if there is a date in the completed column, it will need to calculate
the next date it is due.

Does anyone have any suggestions on how to do this?

Thank you!!