Reopening ticket (problem)

Hello,
I have the situation that we work with several waiters and the waiters are paid by comissions. The more a waiter sells the more he earns. It is a fix amount of 9% which is only calculated statically in the Report. If a waiter makes a mistake after a ticket has been settled, I have to reopen the ticket delete the mistake and then settle the ticket again. The Problem is that afterwards the whole bill is like if I had settled it and the comission doesn´t belong anymore to the waiter, but it is as if I had sold all the items on it.

Is it possible to delete an article from a settled bill without changing the ownership of the bill?