How to Make Cells with Data Validation Lists Return Blank if a previous cell is Blank

I don't really know how to word this....for cells with formulas, I know how to do this.

Ex. You have a formula in cell B2...you want B2 to return a blank if A2 is blank
Syntax for formula in B2 would begin as follows
=IF(A2="","",

Now, pretend that B2 has a data validation list. I enter data in A2 and select an option in B2. I then decide to delete the info in A2. After deleting the data from A2, I want B2 to return a blank. How do I do this?

I'm ready to pull my hair out, so thanks in advance.

~Sandy