What is Soul? What is Spirit? Are they same?
My Dear - Spirit and Soul are two separate entities.
Spirit is comprised of the essence, memories and energy gathered from a living being throughout a specific incarnation, a single lifetime on your dimension.
Soul is the life force consciousness. It is the true Being, the light and life within. Soul is the light being which incarnates into the physical body and resides there for the lifespan of the body and returns to Source when the body dies.
Therefore the Soul can reincarnate while the spirit remains.
A 'ghost' is a Soul which has not returned but instead has remained attached to the Spirit - hence rendering the Spirit stronger and therefore able to be 'seen' on the physical plane. When freed from the attachment to the life lived the Soul will return to Source.
And so oftentimes a Soul will have reincarnated to a new body and a new life but the energy from the Spirit of the past life remains on the physical plane. And so you may experience the presence of departed loved ones whilst at the same time they may have re-incarnated into another physical body.