Removing an identity with Dissociative Identity Disorder

alters are apart of the brain, they are a consciousness, and they cannot be removed. there is splitting, where a singular alter becomes multiple, and integration, where multiple alters become one. there is also dormancy, where alters essentially go into a deep sleep. otherwise it is possible to sort of reform alters, help them get better

There isn't really a way to 'remove' an alter so to speak. There's integration, which is where two alters or a host and alter will come together to create one whole, but that's usually done through many therapy sessions while working through past trauma.