Well, it hasn't happened to me very often, but I had three sales to the same buyer, sent an invoice for the three items with reduced shipping, etc. Problem is, the third book could not be found in my inventory...aaack!! So this morning I had to cancel the third item and send a revised invoice for the other two....TALK ABOUT SMOOTH!!!
Thank you, Gazza, for designing a great invoicing system that allows us to accomplish this with ease...I've said it before and I'll say it again...YOU DA BOMB!!