Name: event-status-declaration
Type: request
Purpose: >
  Declares new event status
Response: event-details
Inherits: message
Elements:
  Event-Id: { required: true, type: identifier, class: event }
  Status: { required: true, type: string, min_length: 3, max_length: 16 }
Rejection-Codes:
  31: Sender is not authorized to declare event status
  41: Event does not exist
  42: Unknown status
  43: Event with status x cannot be declared as y