changing a cell value depending on an If Function/Lookup

[Guest]

I have a lookup function on one worksheet, that will check if the number I
input exists in a named range (accruals) on another sheet named Accruals.
What I want to do is say.

If this number exists then find the cell reference it appears in, in
worksheet Accruals and change the amount under column amount to zero.
These numbers are not sorted but are unique

Po SHeet
PO supplier date amount

Accruals columns - Accruals sheet
Po, supplier date, amount

 

[Frank Kabel]

Hi
could you provide an example?

 

[Guest]

Sheet Accruals
A B C D
Po Number Supplier Date Amount
123 Chris 07/11/04 £100


Sheet P1 - these are paid invoices
A B C D
Po Number Supplier Date Amount
123 Chris 08/11/04 £100

What I want to do is IF the PO NUmber in SHeet P1 appears in the PO number
column in Sheet Accruals, then change the amount in the Accruals Sheet to 0
There are lots of these and not sorted

Chris