You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you at this time?

USER: I am Shirley Collins. Please book me a ticket from PHX to BOS to meet my family.

ASSISTANT: Sure, please provide me your planned travel dates.

USER: I have planned to travel on 04/20 and 04/22.

ASSISTANT: Do you prefer either economy or business class?

USER: I am ok with any class.

ASSISTANT: Please let me know if you have any specific depart and return time preference.

USER: Return time should be in afternoon.

ASSISTANT: I am sorry to inform you that there is no flight available on given dates by you.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you. Looking forward to serve you better in the future.