Modification of child support happens when a non-custodial parent is ordered to pay child support and then something comes up which is preventing him or her from paying the required amount. Some issues which may be a basis for modification of child support include the loss of a job, a medical condition or sickness, the coming of age of the children, etc. In order to have the amount of child support payments modified, the non-custodial parent or his or her attorney must file a request for modification with the court. The judge will then look over any new circumstances in the case and determine whether a modification should be done. If he or she decides it should be, they will calculate a new child support payment amount based on the facts in the case. The non-custodial parent will then be responsible for the new child support payment amount each month. While individuals can file for modification of child support themselves, it is advisable that they hire a knowledgeable attorney to do it for them.