This form must be completed if you received a Mortgage Interest Credit Certificate. If you did not receive this, you can go to Federal > Deductions & Credits > Your Home and click Start/Revisit next to Mortgage Interest Credit Certificate. Answer No to Do you have a mortgage credit certificate? If there is any information already in that section, click the trashcan next to any entry.
If that does not work, you can also try deleting the form from your tax return. Go to Tax Tools on the left menu, and select Tools. Select Delete a form from the popup menu and click Delete next to Form 8396. Be very careful not to click on a different form, as that will delete the information from that form and it will need to be re-entered.