Help with VLOOKUP?

[Dave1979jCIOH]

Lets say I have column A1-A5 labeled as weeks 1-5 and will choose a different
person to go in column B1-B5 each week. Below column B1-B5 in B7-B11 I have
each person's name from which I will choose. Is there a formula or function
that can be used that will replace each person's name with an "X" in B7-B11
as they are filled in each week in B1-B5?

I am thinking it may be some sort of IF statement with a Vlookup formula.
If so, doe that require listing the names again in column B below B7-B11?

 

[Sheeloo]

You can have the following formula in C7 (and copied down to C11)
=ISNA(VLOOKUP(B7,$B1:$B7,1,False),"","X")

It will put an X in Col C if the name in corresponding cell in Col B is
entered in B1:B5, otherwise it will remain blank...