Welcome to Gaia! ::

A doppleganger is more of a mimic, or copy and exists as a separate being and doesn't reside in a host.

If you are talking about a second (or more) personality, it would depend on how that identity came to exist in your body.

If it is a possession where another being/spirit simply decided to move in and either share or take over your body, then it becomes either a battle of wills, or a very deep rooted discussion about why it is in there and convincing it there are other places it can reside.

If it is a split personality created by trauma, or some horrific experience, there are usually conditions that are needed to be met. In theory, the most common are security and safety, guidance and acceptance of some sort. But because most doctors and therapists treat the symptoms and not the cause there isn't much documentation as to a process needed to make this work.

Unfortunatly, I don't have any experience in this area. I mostly deal with mood disorders and behavioural outbursts. Not quite the same. Those I meet, to the best of my abilities, with patience, aceptance, tolerance, understaning, calmness and nurturing. Some of that might be helpful, but again it would depend on the situation.

I really meant more of the lines of your spirit guide coming out to help you fight or temporarily take over your body while you have an O.O.B.E. Something more of that nature. Sorry for not being clear. domokun