You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: David Perez here.

ASSISTANT: How can I assist you today?

USER: I have to visit Austin for a business trip, so could you please help me out with booking of a flight ticket?

ASSISTANT: Sure, I will help you on that.

USER: Thank you.

ASSISTANT: Will you provide your travelling dates please?

USER: Sure, I am planning to go on 01/13 and please book a return ticket on 01/15.

ASSISTANT: Please provide your airport codes that you want to travel.

USER: I want to travel from SFO to AUS.

ASSISTANT: Please give me a moment.

USER: Sure, take your time.

ASSISTANT: Thank you for waiting.

USER: Oh! so sad.

ASSISTANT: Unfortunately, there is no flights found under your details.

USER: Anyway, thank you for the information.

ASSISTANT: Welcome, have a great day.