You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Patricia Walker.

ASSISTANT: Walker, how may I assist you?

USER: I want to travel from PHL to ORD. Can you book a flight ticket for me?

ASSISTANT: Sure, can you please tell me your travel dates?

USER: I want to travel on 08/11 and 08/13.

ASSISTANT: Ok, please wait for a while.

USER: Ok, take your time.

ASSISTANT: Sorry Walker, I did not find any flight available on your preferred travel dates.

USER: That's ok. Anyways, thank you for your help.

ASSISTANT: You are most welcome and have a nice day.