answer: #Person2# helps #Person1# to buy a return ticket on the soft sleeper to Xi'an tomorrow.
documents: #Person1#: Hello, I'd like a return to Xi'an please.
  #Person2#: Certainly. When do you want to travel?
  #Person1#: Tomorrow.
  #Person2#: Ok, no problem. What class of service would you like - soft sleeper or hard sleeper?
  #Person1#: How much is the soft sleeper?
  #Person2#: The soft sleeper costs 600RMB one way and the hard sleeper is 400RMB one way.
  #Person1#: Ok, I'll take a return ticket on the soft sleeper please.