So you say "Why did you make that small change above?"
"Just remove the waiter and the service charge is removed"
Well, no. Once you add a service charge it stays on the ticket. So to remove it we need another Rule which will contain all of the Actions that add the waiters service charge, but we set the Setting Value to 0, and this removes the service charge.
To remove waiter service charge
Create a Rule - Remove Waiter Service Charge
Event Name - Ticket Tag Selected
Tag Name = waitron
Tag Value = 0
Select Actions - {All of the waiters tips actions, ie John - Tips)
Setting Value - 0 <-- set to zero for all actions
Now, save the Rule, and close the Rule List tab. Open the Rule List again and edit Remove Waiter Service Charge rule. Now the only change you need to make is to remove the 0 from Tag Value. Why, because we need tag value to be NULL and this is the only way to do that. Save the rule.
Logout and logon.
Now when you remove a waiter, the service charges are also removed.