I have never done this before. But last night I did have occasion to refuse a red snapper dish as the fish was past it's prime. I asked for it to be removed from the bill. They said they ould only discount 15% because some of it had been consumed. I had one bite, brother had two bites and it was deemed icky at that point. Waitress says that they are eating the same fish (was it ours?) and it was fine. Was I unreasonable in wanting the whole dish comped? The spring rolls were great, the soup was not as good as it has been - good broth, stingy on veggies and tofu.