@startuml

participant "ACM Runtime"
database "ACM Database"
participant "Participant Replica 1"
participant "Participant Replica 2"

"ACM Runtime" <- "Participant Replica 1": [ASYNC] Prepare Automation Composition Element \nInstance Response
"ACM Runtime" -> "ACM Database": Store Automation Composition Element Instance \nResponse Information

alt Is Prepare AC Element Instance Completed?
 "ACM Runtime" -> "ACM Database": Set AC Element Instance SubState as NONE
 alt Are all the other AC Element Instances in this AC Instance in state NONE?
  "ACM Runtime" -> "ACM Database": Set AC Instance SubState as NONE
  "ACM Runtime" -> "Participant Replica 2": [ASYNC] Send sync message
 end
end

@enduml