To change your child's parenting situation you will need to go into the child's profile in your account and change the current parent that is administering them. Unfortunately there is no automated process for this, you will need to go into your account and do it manually.
Can this please be raised as a feature request?
Ideally this should be done from the calendar, the same way that we schedule school and rest days.
For now I will login each week and change it over.
Do you have a REST API that I could call to automated this myself until there is a better way?
I will add this as a feature request. Unfortunately, we don't have an API available to allow you to automate this change.