MESSAGING_CONVERSATION_USER_ROLE_MANAGE MESSAGING Endpoint
  /rpc/messaging/?method=MESSAGING_CONVERSATION_USER_ROLE_MANAGE  
  Object: 392. Click here for more information.  
  Add or remove user groups to a conversation.  
  PARAMETERS TYPE NOTES
  DataReturn Text A comma delimited list of advanced search fields to be returned after a successful save
  Id Numeric  
  Remove Numeric Pass '1' to remove the item
       
  Conversation Numeric Mandatory. You need to be the owner of the conversation.
  UserRole Numeric Mandatory. As per SETUP_ROLE_MANAGE
  Notes Text (2000)  
  RETURN  
  id Numeric
  status ADDED, UDPATED, REMOVED