I'm working with this formula, which gives me [Expected Completion Date]:
=[Planned Start Date]1 + [Expected Days Duration]1
Without values in Planned Start or Expected Days, I get #INVALID OPERATION in the Expected Completion. What's the simplest IF/THEN to use that will return a blank in EXPECTED COMPLETION if we haven't yet entered values in either or both of the other two cells, and returning the original sum from above when there are values in both?