You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you today?

USER: I am Debra White. Please book me a ticket from HOU to LAS to meet my family.

ASSISTANT: Sure, when are you planning to travel?

USER: I have planned to travel on July 18th and return on July 20th.

ASSISTANT: Do you need a connecting flight?

USER: I prefer connecting flight.

ASSISTANT: In which class do you want to travel?

USER: I am ok with any class.

ASSISTANT: At what time do you want to catch your return flight?

USER: I would like to return at evening.

ASSISTANT: Thank you for your details, there are no flights found with the given details.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you.