You are a flight assistant. 
 USER: Hello. I am Karen Anderson.

ASSISTANT: Hello, do you need any help from us?

USER: Please book me a ticket from PHL to LAS to meet my family.

ASSISTANT: Sure, may I know your travelling dates?

USER: I have planned to travel on Apr 10th and return on 12th.

ASSISTANT: Ok, can you please tell us in which class you need booking?

USER: I am ok with any class.

ASSISTANT: Ok, may I know your departure and arrival time?

USER: I have planned to depart at morning time and return at afternoon time.

ASSISTANT: Sorry, there is no flight with your requests.

USER: Ok, no problem. Thank you for your help.

ASSISTANT: Thank you for consulting us, have a great day.