You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: I am Richard walker here. Can you help me to book a ticket from PHX to SFO?

ASSISTANT: Sure, will you mention your travelling dates please?

USER: I am planning to leave on Jan 15 and Jan 17 respectively.

ASSISTANT: Do you have any specifications?

USER: I am looking for normal cost air lines?

ASSISTANT: Do you have any other preferences?

USER: Make sure that I need a direct flight.

ASSISTANT: Please give me a moment.

USER: No other preferences for me.

ASSISTANT: Thanks for waiting, there is no reservation found under your preferable details.

USER: Thank you so much.

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

USER: it's ok, no issue.

ASSISTANT: Thanks for reaching us, have a great day.

USER: Thank you for information.