Can help create a use case diagram based on this use case:

Use case title: Assign available ambulance crew to a case

Primary actor: Dispatcher

Level: User goal

Stakeholders: Dispatcher, ambulance crews, patients

Precondition: There is an available ambulance crew and at least one case awaiting dispatch.

Minimal guarantee: The available ambulance crew is successfully assigned to the case.

Success guarantee: The assigned ambulance crew arrives at the location of the case and provides appropriate medical care to the patient.

Trigger: A case is waiting for dispatch and there is an available ambulance crew.

Main success scenario:

The dispatcher views the list of cases awaiting dispatch.

The dispatcher selects an available ambulance crew to assign to the case.

The dispatcher assigns the selected ambulance crew to the case.

The assigned ambulance crew receives notification of the case details and proceeds to the location of the case.

The assigned ambulance crew arrives at the location of the case and provides appropriate medical care to the patient.

Extensions:

If there are no available ambulance crews, the dispatcher requests availability from other crews or reassigns another crew from a lower priority case.

If the assigned ambulance crew is unable to reach the location of the case or encounters any issues, the dispatcher takes appropriate action, such as reassigning the case or providing additional support.