You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Charles Lewis.

ASSISTANT: What kind of services are you looking for?

USER: I am very passionate about astronomy, so I would like to visit Space Center Houston.Could you please book a flight ticket for me?

ASSISTANT: Yes sure. Let me know, when you want to start your journey?

USER: I would like to start my journey on 11/20 and return on 11/22.

ASSISTANT: May I know your travelling location codes?

USER: Sure, my nearest airport is SEA, so I would like to travel from that airport and I will land on IAH.

ASSISTANT: Ok, please wait for a moment.

USER: Ok, take your time.

ASSISTANT: Sorry. There is no flight is available for you. Do you want to know anything else?

USER: No problem, I will go by another way. No, I don't have any queries right now. Thank you for checking.

ASSISTANT: Ok. You are welcome.