While most areas call for the seller to disclose any/all known material facts, I have a difficult time believing that an omission of a couple of plainly visible cracked tiles is cause for much concern. Many areas consider such things cosmetic. I highly doubt that minor cracked tiles would be ruled by a legal authority to be a material fact that would have affected the buyer's decision, had they been aware of it, to purchase the property. As such, your friend should simply say "my bad" and correct the disclosure to reflect the cracked tile. Further, in my area, the disclosure does not have to be provided until after the contract has been fully executed. As such, in Arizona, there would not be a potential disclosure issue if the change was made and resubmitted to the buyer within 5 days of contract acceptance.