Biological clothes washing powder/liquid diluted with warm water may help, also a weak solution of milton or common household remedies with a bleaching effect, eg lemon juice. If it is lino type vinyl flooring that is stained, this suggests to me that the topmost sealing layer of the vinyl has broken down and the stain is in the sponge like layer underneath. this sadly will make it really hard to remove the stain as the stain remover will have to permeate all the little holes and crevices where the stain is now lodged. as an aside, if the room user is not taking medication which colours the urine, urine which stains tends to be a sigh that the person who produced it is not drinking enough watery fluid, but you probably are aware of this.