Although length of time is one consideration, it is not the only factor taken into consideration when an allegation of child abandonment is made in a child custody case, according to "Child Custody A to Z" by Guy J. White.The underlying function of an allegation of abandonment in a child custody case is to permit the court to establish a new custodial arrangement, according to "Child Custody A to Z." Actual abandonment is considered a material change of circumstances sufficient to permit a court to issue an order altering the existing custody arrangement, according to Cornell University Law School.The test applied to the alleged abandonment of a child is the intent of the departed parent, according to the American Bar Association Section of Family Law. For example, if a custodial parent is forced to leave the child with a responsible adult for an indefinite period of time due to a true, verifiable emergency, a court is not likely to consider such a move abandonment, even after a week or two. However, if a custodial parent simply leaves with no explanation, a court may deem the departure abandonment after a day or two.If the custodial parent appears to have abandoned the child, as the non-custodial parent you need to file a motion to change custody, including a request that the court grant you emergency custody, at least on a temporary basis. The urgency in filing such a motion depends in part on how long the custodial parent is gone, the expressed intent of the custodial parent in leaving and the location of the children since the custodial parent departed.A common misconception is that the non-custodial parent always obtained custody of a child when it appears the custodial parent appears to have abandoned her. The reality is that even if the custodial parent is gone for an ever increasing period of time, if the non-custodial parent has not maintained regular contact with the child, and he is in a safe location, the court may elect not to approve a custody change.Another time-related consideration associated with the issue of child abandonment and custody is a custodial parent who routinely leaves the child for short and yet indefinite periods of time, without a valid reason. Although the custodial parent may leave the child for less than a day at a time, the cumulative amount of time and effect in the court's mind may warrant a change of custody.