Sorry to hear about the knife damage! We do sell replacement leather and if you are in Boston we could help you remove the damaged leather and install the new pieces. It is a difficult process so I'm not sure it is something you would want to undertake on your own. There are companies online that will sell you new straps and have instructions for changing the leather. Whether or not replacement leather would fit depends on the manufacturer and quality of the existing chair. Dimensions can vary slightly from one manufacturer to another and the quality of the leather and the thickness of the steel frame varies depending on the manufacturer. There are copies made in China that sell for $200-$400 and it is barely leather with thin metal tubing and plugged end caps, there are good copies like ours that are comparable in quality and construction to the original with welded end caps and then of course there is the licensed version from Knoll. If it is from a good Italian manufacturer or from Knoll then our replacement leather should work fine. If it was an inexpensive reproduction then it probably is not worth replacing the leather and our leather might not match or fit the frame. Please advise if you have any other questions or if you would like pricing for the replacement parts. Good luck!