In re Marriage of Debra N.

Court properly modified terms of parties' joint custody agreement and awarded sole custody of daughter to her father. Court found that mother had engaged in pattern of interference and manipulation of father's relationship with intent to diminish or eliminate father's ability to be fully engaged and active parent. Court was not bound to follow recommendation of court-appointed 604(b) expert that court award mother sole custody; expert did not state that father was an unfit parent, and stated that child was attached to both parents. Although father did not specifically request sole custody, court has broad discretion to alter custody or visitation once issue of custody is placed before court. (LAVIN and FITZGERALD SMITH, concurring.)