Human urine odours are much different than pet urine odours, requiring different techniques. When it comes to removing a stain or odour, it's best to try as many techniques as it takes to diminish the smell completely. It's best to try the most cost effective techniques first, like using vinegar, before purchasing more costly odour-eliminating products which contain enzymes.
Sprinkle baking soda gently over the area where the accident occurred. Let the baking soda set for a couple of minutes.
Spray water from a water bottle over the spot and baking soda.
Use a cloth to rub the water and baking soda mixture into the spot. Make sure that you run the mixture into the spot well so that you see no baking soda. Also, make sure that the spot is mostly dry before continuing.
Pour distilled white vinegar over the spot. Blot heavily with the cloth or paper towels until the spot is dry. Rinse the spot once again with water. Don't spray any odour-eliminating chemical over the spot while it dries. It will smell vinegar for a few hours, but the smell should be eliminated.
Try a pet cleaning with natural odours if the odour still persist. This should be your last and final option if the vinegar and baking soda mixture doesn't completely kill the odour.