A retreat is not about teaching a particular religious perspective. A contemplative retreat respects the spirituality of all human beings. It is an experience where each person is given the space and opportunity to connect with the realities of their own life, identity (true selves) and spiritual journey. Formal religious beliefs, as such, can be enormously varied amongst those who go on retreats. You may have a background in Christianity or another faith system, or consider yourself to be totally secular. The starting point for each retreatant is unique.
As human beings we are all on a journey of discovering who we are and finding our unique contribution to the wellbeing of the world around us. If you have a faith background, you will find many ways in which your reflections during a retreat connect with your experience of God, but your retreat will not be governed by your religious training. Some of the refreshment of the retreat experience will be drawn from the wisdom of the Christian Contemplative tradition. However, other resources such as psychology or the contemplative insights of other faith traditions may enrich your times of reflection.