You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Lisa Nelson.

ASSISTANT: How can I assist you today?

USER: I have to go New York next week for giving a seminar to students about science and technology there, can you please book a flight ticket from Phoenix?

ASSISTANT: Sure, will you mention your airport codes please?

USER: I want to fly from PHX and destination airport is EWR.

ASSISTANT: Please provide the preferable dates of your journey.

USER: My departure date is 08/26 and please book my return ticket also on 08/28.

ASSISTANT: Please give me a moment.

USER: Ok.

ASSISTANT: Thank you for waiting, there is no flights available under your preferable details.

USER: Oh! it's ok no problem, I will go with another airline service. Thank you for your service.

ASSISTANT: My pleasure, have a great day.