Add participant

mutation AddParticipant($conversationId: ID!, $input: AddParticipantInput!) {
  addParticipant(conversationId: $conversationId, input: $input) {
    agentId
    avatarUrl
    conversationId
    displayName
    id
  }
}

{
  "conversationId": "",
  "input": {
    "userId": ""
  }
}