I'm not sure I understand what you are asking. If the below options don't
help you get the answer you are looking for, please post back with step by
step instructions as to what you are looking for. It's time for me to retire
for the evening, but I will check back tomorrow to make sure you ulitimately
received a satisfactory answer.

If you want to check for a match and return the date only if there is a match:
=IF(ISNA(VLOOKUP(Sheet1!S3,Sheet1!$A$3:$A$400,1,0) ),"No
Match",VLOOKUP(Sheet1!S3,Sheet1!$A$3:$A$400,1,0))

**I typed this formula here manually. If it malfunctions, it's probably
because I left out a parentheses**

As for the sheet2 and sheet1 issue, I don't know what cell in column T you
started with, so I assumed T3 only because it matches S3 in the other formula:
If you want to return Columns T-AI only if the value in Column S matches any
value in Column S, then put this in T3 on Sheet2:

IF(ISNA(VLOOKUP(Sheet1!S3,Sheet1!$A$3:$A$400,1,0)) ,"",Sheet1!T3)

Copy this over to AI. Copy down as far as needed as well.

Here is where I'm a bit confused with your post:

I am doing something where I am comparing Column S to Column A. I used the
formula you provided, but I don't want it to say "Match" or "No Match". I
want it to say whatever is in the cell (the date). What would I do to make
it return the value of the cell?


What do you mean by 'whatever is in the cell'? You want to return some value
even if there isn't a match? If so, the value from what cell?

To be clear, can S3 match any value in A3:A400? Or does it have to match A3?
The answer to this question may make a different approach to the one I am
taking a better option.

tj