bulk action on complex dates page

When a change occurs to an already created workshop it is usually for all complex dates within the workshop. We currently have to go in and manually change the information (most of time it's a change to the class time, but could also be things like location, room etc) by making the change to each individual date.

It would be very helpful to have a bulk function like in the resulting areas where we could choose which dates we want changes applied to and what those changes are.