Generally you should give 2 weeks for the changes to take effect to allow the parents the time to make the necessary adjustment .... Such as broaching it with the work place to get different working hours or to buy another car seat so one parent can drop off and another can pick up.... This notice would be equal to the notice you require for termination by either party. Any contract not signed by a certain date would signify that care is no longer required. Will a 9 hour day be enough for parents to be able to drop off and commute to work? .. Where I live I have to open early (6:45) to allow enough time for parents to get to work with the rush hour traffic and I'm closed at 4:45 which is a 10 hour day but not one family uses the full 10 hours.