I don't know why everyone here is saying you can't do it. I do it with every paycheck. I have Quickbooks Desktop. No you can't change amounts, but you can add customers and classes after the fact. I have been doing it for the last 14 years! Open the paycheck, then click on "Paycheck detail" Don't change any $$ amounts, but you can change the number of hours (as long as the total matches what was originally there). You can add lines, customers and/or classes.
I have heard that you can't do this with Quickbooks Online, which is why I'm dragging my feet to go there.
