Help needed with VLOOKUP to fill in cells automatically but with exceptions

I'm using a really basic example to try and ask this question and figure out what formula I need. But basically - in the attachment on the "Sample" worksheet - if I type someone's name in Column A, a number automatically appears in Column B. That's what I want. HOWEVER, if there is a value in either Columns 1 or 2, I want a different number to appear. Or for the cell to just return blank. What do I need to accomplish this?

**********OK - TRYING THIS AGAIN. I am new here and there are so many rules for how to even post, so bear with me.

I can't share my actual spreadsheet because it contains sensitive information so I tried to re-create what I need in this sample worksheet. If you look at the worksheet called "SAMPLE" - Column "B" will automatically fill in with the corresponding person's code (found on the CODES worksheet) as I type people's names in. However, what I want is for that code to fill in UNLESS there's something in either column C or D. If something is in Column C, I want the code to be "1111" and if something is in Column D, I want the code to be "2222." Does this help? Attached is an updated spreadsheet.

What different number do you want to appear? Provide a few examples.

In future, please give your threads more descriptive titles - this one could do with improvement, please, as it is too generic.

Please update the thread title, as requested. Then provide a workbook that shows what you want, not a formula that does not give the desired result.

Also, your formula is only coincidently giving the correct answers...
=VLOOKUP(A2,CODES!A1:B4,2,FALSE)
You need to "absolute" the range refs so they dont change as you copy down...
=VLOOKUP(A2,CODES!$A$1:$B$4,2,FALSE)

I was hoping the OP would update the thread title - I don 't understand the requirements well enough to suggest a good title.

I agree, the title is vague, but the question is even more so