Sounds a little crazy or like I see dead people from the The Sixth Sense movie. Is very useful, especially when the unexpressed emotions and feelings relate to people that for one reason or another are not in your life. Deceased, lost contact and so on. Relationships do not end always when the physical relationship with the other one finished, but when we let go. And how to let go when we have a number of unexpressed emotions that we bottle inside. In the same way we do not always express all our emotions to people we are currently in relationship and the expression of the buried emotions sometimes in the absence of the other person can help communicate from a place of love and peace with the other one.
So how to do it? How do I do it? I imagine the other person in front of me and I say everything that comes, including crying, shouting or tenderness. Everything that comes without judgement or attempt to make them sound better. That releases what is long due to come out and makes space for new emotions and resolutions.
Sometimes I speak in the same fashion with my little me, the child that I was as a way to reconnect to old emotions, desires or needs. Time is not linear and that emotion release can heal in both your past and your future.