Most cases of gingivitis can be reversed naturally with daily tooth brushing and flossing.
Gargling with apple cider vinegar and also with regular mouthwash and using a water floss device can help to reverse gingivitis before it gets too severe.
While at home natural remedies can help with reversing gingivitis it's also recommended that if you really want to get rid of gingivitis is to see a dentist.
If possible you should go to a dentist for regular teeth cleaning by a dentist or dental hygienist which can help prevent the gum disease gingivitis from getting worse.
Once the gum disease gets worse then it cannot really be reversed.
You can also brush your teeth with baking soda and water as a natural toothpaste.