The process of Parenting Plans:
If parents end up in court at some later date, the court will consider the terms of the most recent parenting plan when making parenting orders. The court will also consider the extent to which both parents have complied with their obligations in relation to the child, which may include the terms of a parenting plan.
The parents can agree to change parenting arrangements by a parenting plan (given the court order allows it and was made after 1 July 2006). This can be made without going back to court.
Unless there are issues of violence or abuse, the law presumes that it is in the best interest of a child for the parents to have equal shared parental responsibility.
If the child spending equal time with both of you is not appropriate, you could consider an arrangement that allows both parents to spend substantial and significant time with the child.