Ideally, you should get your Pionus parrot a companion. This is because parrots are social birds, and can live in flocks of up to 30 individuals in the wild.
If your Pionus parrot has a companion to keep them company, they’re likely to be much happier as a pet, too. They won’t get as lonely as they would if they were on their own. Your Pionus parrots would be able to keep each other entertained when you weren’t home. It should also make the birds more confident.
However, if your Pionus parrot has been on its own for a while, you will need to acclimatize them to the other bird before you keep them in the same cage.