It would be possible for there to be a court order specifically barring a parent from visitation, etc., except on the permitted days. However, in the vast majority of cases, the court order merely sets the required minimums--i.e. the days when a parent must be allowed to see the child and is supposed to spend time with him or her. Such orders do not bar the parent who would normally have custody on a given day from voluntarily allowing the child to see the other parent on that day; in the typical case, the parents can, so long as they both agree, deviate from the schedule. It's a good idea to double check the language of the order, but again, this should be fine so long as its voluntary.