Admin: how to handle enrolled users of shift when downsizing it

[uppzz]

Describe the bug
If a shift is downsized (it's number of required helpers is reduced) in admin and then has a lower number of required helpers than the number of already enrolled helpers for that shift, none of the helpers is removed from this shift (and not notified about it).

Expected behavior
???

Screenshots

[christophmeissner]

What is the expected behaviour? In fact, I'm not even sure, if we should handle this edge case automatically at all, but should instead require the manager to reduce the then possibly overbooked number of helpers manually when downsizing a shift.

[uppzz]

yes i think that is a good solution that the manager has to take care of it. but can the manager even take an already registered helper out of a shift? well he could write to the last helpers and cancel them manually would need then but a request from the system

[cyroxx]

Downsizing a shift is not an edge case, but a totally valid case for shift management.

As a shift manager, when downsizing a shift, I want the system to detect a then-overbooked shift and suggest a list of helpers that will be cancelled (the ones that enrolled last). I can then either just confirm the suggested list or make changes to it (choose the required number of cancellations among all enrolled shift helpers, suggested list is pre-selected). The helpers of the cancelled shifts are notified.