There is no "I" in "You"

[Thumpalumpacus]

... umm just A's memories and experiences are transferred to B's body. You wrote that yourself, why are you asking me?

And did you not read anything I wrote so far?

'self' is the collective summation of all your memories, experiences and all of the factors creating and effecting them including physical attributes.

If so, then how does A disappear?

It's your hypothetical -- why are you asking anyone else to flesh it out?

Lazy thinker spotted.