You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: Can you help me to book a flight ticket from PHX to LAS.

ASSISTANT: Sure, I will help you. Please let me know your travel dates.

USER: Ok, please can I know the dates May 17th and May 19th?

ASSISTANT: Thank you. May I know your name?

USER: Yes, my name is Susan Perez.

ASSISTANT: Thank you. Could you please let me know your class preference?

USER: There is no class preference.

ASSISTANT: Ok, please wait for a while.

USER: Ok, please book a flight which return time is during morning.

ASSISTANT: Sorry. As per your requirements, there is no flight available on your given travel dates.

USER: That is ok, thank you for assisting me.

ASSISTANT: You are welcome and thank you for choosing us.