Resource/People planning plugin

Hi All on WordPress,

I’m completely new to WordPress so excuse myself if asking the wrong question and the wrong location.

I’ve been approach by an association running a WordPress web-site to add functionality regarding resource (people) planning. For this I’m searching for a good and flexible plug in.

What they want to achieve, a couple of days per year the association requires a X amount of people to be available for work. Instead of managing this via Excel and email they want to have a plugin that the people can allocate themselves to those days via the web-site (wordpress) themselves.

On day X the association requires 6 people, then the various people are being invited to visit the web-site and then they can sign in for that day. When 6 people are assigned that day is full and it is not possible to sign in on that day.

Also it should be possible to move from one day to another day, the person/visitor should be able to reschedule to another day.

Also I want to have some administration arround this allocation, how many people have been allocated on which days for a certain period. Overviews need to be send via email.
And people need to be informed if they have not signed it for a X amount of days per year.

These are maybe complex requirements but I was hoping there is a plug in available that can do such a thing.

Looking forward to the responses and suggestions.

Regards. Rene