class Decidim::Meetings::LeaveMeeting

def call

Broadcasts :ok if successful, :invalid otherwise.

and the registration exists.
Destroys a meeting registration if the meeting has registrations enabled 
def call
  @meeting.with_lock do
    return broadcast(:invalid) unless registration
    destroy_registration
    destroy_questionnaire_answers
    decrement_score
  end
  broadcast(:ok)
end