As soon as the patch for bug 2830 is applied, if a reserve that already has a waiting item is filled by an item with a different barcode, the original reserve is deleted. That is good. A slight enhancement to that behavior might be to also alert the librarian that there might be an item on the hold shelf. i.e. the system pops a message that indicates "I just deleted a reserve that was in waiting status, go get it off the hold shelf and send it to someone else or reshelve it"