Request to change the booking by booker

A booker can requests a change in a booking or reservation.

In the basic setting, the changes will be accepted automatically. 

You do not want that?
You can set this in your venue profile.
Go to your venue list:
Click 'edit' on your venue, choose the tab 'booking' and scroll down to 'Autoapproval of changes'. 

When selecting 'disabled' you will get a notification with the request of change. You as a space provider have to actively accept or reject the change.