I have cell I13 which calculates the tax amount of an item. I have now set up
a check box, when it is clicked it will display a user form asking to user to
enter an alternative tax amount and press €œOK€� button. I have linked the €œOk€�
buttons result to O13.

How do I write the code if I want the O13 result to overwrite I13 only if it
is checked and if it is not checked €“ I13 calculation will remain?