My BIL and SIL are taking their kids to WDW in February. They are 8 and 5. They are doing 2 park days with no hopping. They are wondering if they should do Magic Kingdom both days or MK one day and AK the other with a day in between. My first thought is to reserve MK the first day and then AK the second and if then they want to go back to MK the second instead they can change the reservation from AK to MK. My question is how hard is it to change the reservation from one park to another? Is there a way to check park availability before canceling? I have only been to WDW once since the pandemic last December and we did not run into this so I did not pay attention and it was also almost a year ago. TIA for your help as I do not want to give bad advice.