title: Sabre: "UNABLE TO VERIFY MCT" error in PassengerDetailsRQ
body: <p>Sometimes I noticed I get this error in <code>PassengerDetailsRQ</code>.</p>
  
  <blockquote>
    <p>UNABLE TO VERIFY MCT FOR SEG 01 AT MAA</p>
  </blockquote>
  
  <p>I tried calling  <code>EndTransaction</code> without passing <code>UpdatedBy Element</code>, then when I again call <code>PassengerDetailsRQ</code>, I got the same error.</p>
  
  <p>What could have gone wrong, or am I missing something ?</p>