Is there a wayto prevent order more of an item than what they have already turned in?

[okla76]

Hello,

I have been searching for a way to accomplish what I am trying to do and can't find it. Here it is:

Call A1 is "Request Quantity"
Cell A2 is the "Turn In Quantity"

Cell A2 (Turn In Quantity) is always filled out before Cell A1 - It can contain any number between 1 and 100.
Cell A1 (Request Quantity) is always filled out after Cell A1 - It can only contain a Number that is equal to or less than the number entered in Cell A2.

The goal is to make it where the user fills out the workbook and cannot order more of an item (A1) than what they have already turned in (A2).

Any help is greatly appreciated.