"Yes. Your call sign is your unique identity as a Capsuleer: if you changed it, and a single cloning station that you had a clone with didn't get the memo, they could end up waking a 'you' under your old identity and a 'you' under your new identity. They might not even be recognizable as the same person: we can do extensive cosmetic resculpting, extending even to bone structure. So long as you stay the same sex and ethnicity, you can have basically whatever human body you want."