The court never assumes that decisions regarding child custody arrangements are final and never can change. That is why the court allows modification requests.
People change and situations change over time, which means you may have a time in the future when you want to ask for a change to your visitation or custody order. The Judicial Branch of California explains that the court requires a change in circumstances to request a modification in most cases. In addition, you have a right to request changes every 2 1/2 to three years as a general rule.
You have two options when it comes to modifying your agreement. You can go to the court and request the change, or you and the other parent can reach an agreement on your own. Ideally, you want to try to agree outside of court. It will save time and money. It also makes it easier for everyone when both parents get along and can compromise with each other.
In most cases, before the court will hear your case, it will require you to try to figure it out on your own through mediation. Mediation is a guided negotiation where a neutral third party helps facilitate talks between you and the other parent.
If you do end up in court, you will have to show the judge that there is a substantial change that serves as a reason for the requested modification. You also must show that making any changes will be the best thing for your child. The court will never make changes that are not in the best interests of the children in a case.