Message flows
A message flow is a BPMN standard dotted arc. A message flow is a
non-sequential link between pools that represents the communication between
different processes and participants with no specific order for the messages.
You do not need to fulfill all message flows for each instance of a
process.

1 | Message Flow |
You can add a message flow link between:
-
Two nodes in different pools
-
A node in a pool to a different pool
-
Two pools
Note You cannot use a message flow to link nodes in the same pool.