Are you and your former partner discussing the future care arrangements for your child or children? If so, perhaps consider entering into a Parenting Plan.
It is a private agreement between two parents which can detail the agreed arrangements in relation to a child/children. This includes provisions for the time, school holidays, special occasions, telephone communication, etc.
A Parenting Plan when signed by both parties then comes into effect. And it is flexible and can be updated as and when the parents require or at important junctions in a child’s life i.e. when commencing Prep.