If a home that is listed on HomeExchange is sold or you need to move for another reason the best would be to create a brand new listing with all the new information. This way your exchange partners will see correct information and it will avoid potential confusion. To see how to add new listing, please check this article.
For your old listing, best would be to remove it from your account to avoid confusion. To do so check this article.
All the reviews you had on your old listing will now be visible only on your profile page. This way other members can still see your experiences from your previous home.