Trial court denied father's motion to reduce child support. Father had burden of proof to show substantial and continuing change of circumstances. Even though at time of agreement youngest child was age two and no income was imputed to mother and at time of hearing child was age four and mother was still not working, trial court was unable to find father's income from self-emloyment due to lack of documentation. The court's conclusion that there was insufficient evidence to find a change in circumstances that would justify modification was affirmed.