Source : Webster's Revised Unabridged Dictionary (1913)

Booking clerk \Book"ing clerk`\
   A clerk who registers passengers, baggage, etc., for
   conveyance, as by railway or steamship, or who sells passage
   tickets at a booking office.

Source : WordNet®

booking clerk
     n : someone who sells tickets (e.g., theater seats or travel
         accommodations) [syn: {ticket agent}]