Your schedule rules could be different during the holidays. This is why you can add as many schedules as you want to your 2houses calendar. The system will know which one to display.
Here is how to do this:
First, click on “Calendar” on the upper menu, then “Parenting schedules” and then click on “Create a parenting schedule” to add a second schedule.
Select children concerned by the holiday schedule and your schedule model (Joint custody, main custody,....) or create yours manually:
Follow the prompts and save your schedule.
The new schedule will superimpose the standard one for the concerned period (If the schedule is on top of the list).
You can also make change request if this is for a few days:
https://tools.2houses.com/agenda/change_requests