You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you today?

USER: Please book a ticket to Seattle, SEA to overview the city. Can you please help me for booking?

ASSISTANT: Sure, may I know your source airport code?

USER: My source is Las Vegas, LAS.

ASSISTANT: Ok, may I know your planned travel dates?

USER: My travelling dates are Apr 12 and Apr 14.

ASSISTANT: Do you have any limits on number of connections?

USER: Yes, I want single connected flight.

ASSISTANT: Do you have any airline preference?

USER: I prefer normal-cost airline.

ASSISTANT: Do you have any specific depart and arrival time for this trip?

USER: No.

ASSISTANT: Do you have any class preference?

USER: No.

ASSISTANT: Thank you, may I know your name for the documentation purpose?

USER: Sure, Brandon Parker here.

ASSISTANT: Do you have any another preferences on this journey?

USER: No.

ASSISTANT: Unfortunately, no flights available on your requirements.

USER: Ok, Thank you for your service.

ASSISTANT: Welcome, thank you for reaching us.