Hello Oli,

Thanks for reaching out to us. A customer can cancel his appointment through the Customer Panel or via the cancelation link in notifications emails. You can configure this by adding a placeholder in notifications template. An admin doesn't have the option to approve the cancelation, since when it happens, an employee will get a notification that i has been canceled and you will be able to see this is in the backend, in appointment settings.

Regarding the events, we have an event list, where the events are displayed based on the date, so you will see something like this 

Unfortunately, currently, there is no option to change the view of the event list. I hope it helps, if you have any other questions, feel free to ask.