@startuml

actor User as u
collections LOMS as l
database OrdersStorage as os
database StocksStorage as ss

u -> l : gRPC Loms.OrderCancel\n\t- orderID
activate l

l -> os : order.GetByOrderID()
l -> ss : stocks.ReserveCancel()
l -> os : order.SetStatus(cancelled)
deactivate l

l -> u : Response: OK (code_id=0)

@enduml