I'm not sure what the landlord means by changing diamonds. The landlord wants to ask if you will exchange your original diamond for another one? The possibility of this situation is very low, because first of all, there will be no loose diamonds of various sizes in the jewelry store. If the landlord is afraid of shoddy, you can rest assured. I don't know the style of the landlord's ring, but I don't have to worry about the number of carats of the landlord's diamonds below 30 cents, because I am a diamond jeweler myself, and diamonds below 30 cents are not very valuable, so the jewelry store will not take such a big risk to exchange them.