Basit,
According to the link below, only time you use 4797 for your rental property if you are in the business of renting properties to earn a full-time income. If you have just one rental property and renting out properties is not your main income, you need to report the loss in schedule D. It is a capital loss, not ordinary loss. Am I missing something?
Is Rental Property a Capital Asset and How to Report It? | Taxhub (gettaxhub.com)
"Although the most accurate answer for the classification of a rental property sale would be “it depends,” the vast majority of the people will have a capital gain or loss on their hands. The only other alternative is to have something known as the “sale or disposition of business property” that gets reported on Form 4797. Even in this case, however, your long-term gains will be classified as capital. The main difference is that your loss is ordinary, and the most that you can deduct is $3,000.
The only time where you will have to submit Form 4797 over traditional capital gain form, which is Schedule D, is when the asset was business-held. In other words, you must be in the business of renting properties to earn a full-time income. Since most people in the U.S. use rental properties to generate supplemental earnings and are not in the full-time real estate business, it comes as no surprise that From 4797 rental property sales are nowhere near as common as the Schedule D ones."