I am not sure how to do this, but I hope it can be easily accomplished.

I would like to have Cell A1 to have a drop down box to choose data 1,2,3,4

Now, I would like the same for Cell A2 except eliminate the choice that was
chosen in cell A1.

So, if I choose 3 for cell A1 then my choices would only be 1,2,4 for cell
A2. Is this possible and how do I do it?

TIA, Tim