title E2 Instance Keep Alive Flow - E2TShutdownManager
participant E2TShutdownManager as E2M
participant E2tAssociationManager as EAM
participant E2TInstancesManager as E2TM
participant E2T instance 1 as E2T1
participant E2T instance 2 as E2T2
participant rNib DB as RNIB

E2M->+E2TM: GetE2TInstance(e2tAddress)
E2TM->+RNIB: GetE2TInstance(e2tAddress)
RNIB->-E2TM: E2TInstance {e2tAddress, associatedRanList}
E2TM->-E2M: E2TInstance {e2tAddress, associatedRanList}
note over E2M: If Instance is already in the middle\nof deletion process - return 
E2M->+E2TM: SetE2tInstanceState(e2tAddress, currentState, TO_BE_DELETED)
alt error
E2TM-->E2M: error
note over E2M: Log it\nSTOP
else success
E2TM-->-E2M: ok

note over E2M: cache associatedRanList

loop each ranName in associatedRanList
E2M->+RNIB: GetNodeb(ranName)
RNIB->-E2M: nodeb
note over E2M: nodeb.E2tAddress=""\nnodeb.State=DISCONNECTED 
E2M->+RNIB: UpdateNodeb (nodeb)
RNIB-->-E2M: ok
end

E2M->+EAM: RemoveE2tInstance(e2tInstance)
note over EAM: Detailed in a seperated sequence
alt error
EAM->E2M: error
note over E2M: Log it\nSTOP
else success
EAM-->-E2M: ok