first of all, if you have any green leaves at all, it isn't dead. If you have more than one, I would try to take a cutting and root that in a new pot using rooting hormone if it is a "woody" type stem, and just in water if it is a softer stem. After that, I would say that if the decline in the plant is very recent, check the location, lighting, temperature, and water for changes. some plants won't tolerate even subtle changes. If you can post a picture, I am sure that someone can give you more specific help. Good luck and great gardening.