Hello! I have a Mother and Daughter who jointly owned a home. The home was sold in 2018. The daughter reported the home sale on her tax return for the full amount. Now my client(the Mom) has received a letter from the IRS that she did not report a home sale on her 2018 Tax return. I saw from the letter that she was issued a 1099-S for half the sale price of the home. I guess the daughter was also issued a form 1099-S for the other half. But the sale of the home was already reported in full. How to proceed? Thanks.