How to put multiple value in different cells if a text exist in an other cell

Hi all

Let me explain my problem in the simpliest way i can.
I have 2 excel sheet like:

First sheet:

Andrea YES
Steve YES
John

Second sheet:
On the second sheet these names can be found multiple times (for example 'John' as well)
and if I put a YES in sheet 1 after 'John' then I would need Excel to put YES to every John's in sheet 2 automatically.

Can I do it with formulas or a script?

You can do it with a formula (let's say in cell B2 of the second sheet) along the lines of:

=IFERROR(VLOOKUP(A2,SHEET1!A:B,2,0)&"","")

where it is assumed that column A of Sheet2 contains your names. Copy this down as required.

Hope this helps.

Pete

P.S. You might need to change the commas ( , ) in the formula to semicolons ( ; ), depending on your regional settings.