Some conversations among multiple participants require one participant to play a special role, e.g. to act as a coordinator.
How can a set of participants agree on a single participant assuming a special role?
- Participant implementations can fail, making a fixed leader assignment unreliable.
Use a distributed consensus algorithm based on Paxos to elect a leader.
Leader election is a common distributed algorithm problem  with a number of proven algorithms.
 Distributed Algorithms, Lynch, 1996, Morgan Kaufmann