This is a popular trope in anime, manga, and modern fantasy novels. If you are trying to write a story, a roleplay post, or a caption for Facebook about a character discovering their friend is a reincarnated soul, the key is to move away from a flat announcement and toward an engaging narrative.
My bestie complains about 'modern music' and drinks black coffee while staring into the distance. I always joked he was an old man. Turns out, he actually is . He remembers a life from 100 shinseki no ko to o tomari dakara de na facebook better