It is possible to put 2 different types of birds together although not recommended. If you're interested in another breed, it should be the same size as your present bird (beak too) and require the same living conditions. Introduce them gradually placing the new bird in a separate cage until they are used to seeing each other without showing any aggression. Then you can put them together for short periods of time to begin with. If all goes well, you can increase the time together until they can be in the same cage. Take the time to observe them making sure it's safe to leave them together.