Control a cell from other cell

[dushkin]

Hi guys,
I have the following challenge:

I have 2 cells:
The first one is being periodically updated automatically by some 3rd party script. It may be full or empty.
The second one is being updated manually whenever the first cell is populated with some value.

Is there a way to make sure, that when the first cell becomes empty, the seconds will be emptied as well automatically?

Thanks

 

[dushkin]

I didn't find a way to edit the question so I'll rephrase here:

The second one is being updated manually by whenever I notice that the first cell is populated with some value.

 

[dushkin]

...by me...