You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you today?

USER: i want to fly to Denver with direct flight to meet my grand parents, can you please help me to book a flight ticket?

ASSISTANT: Sure, we are euphoric to help you.

USER: Thank you.

ASSISTANT: Kindly mention your airport codes.

USER: My source airport code is SEA and my destination airport code is DEN.

ASSISTANT: Please share me your travelling dates.

USER: I intend to depart on Dec 31st and my return date will be on Jan 2nd.

ASSISTANT: Is there any other requirements to make your trip?

USER: No more specifications for this trip.

ASSISTANT: On which name should I book the flight ticket?

USER: Please book the ticket with the name Katherine Miller.

ASSISTANT: Ok. Give me a minute.

USER: Sure.

ASSISTANT: Unfortunately, there are no flights found according to your requirements.

USER: That's ok, I'll choose any alternative to reach my destination. Thank you.

ASSISTANT: Thank you for reaching us.