@startuml
skinparam monochrome true
skinparam packageStyle rectangle
skinparam shadowing false

title System Sequence Diagram (SSD) - Alternative One

autonumber

actor " Human Resources Manager (HRM)" as HRM
participant ":System" as System

activate HRM

    HRM -> System : asks to assign a skill to a collaborator
    activate System

    System --> HRM : shows available skills list and asks to select one or more
    deactivate System

    HRM -> System : selects one skill
    activate System

        System --> HRM : requests data (i.e. reference to collaborator)
    deactivate System

    HRM -> System : types requested data
    activate System


        System --> HRM : shows all data and requests confirmation
    deactivate System

    HRM -> System : confirms data
    activate System

        System --> HRM : displays operation success
    deactivate System

@enduml