You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I am Alexander Anderson, I am planning to go for an outing at Houston. Can you help me to book a ticket?

ASSISTANT: Sure, may I know your travel dates please?

USER: I am planning to start on 07/21 and return on 07/23.

ASSISTANT: Ok, may I know your airport codes please?

USER: My nearby airport codes are OAK and IAH.

ASSISTANT: Ok, hold on for a moment.

USER: Take your time.

ASSISTANT: Sorry Anderson, there are no flights available on that route.

USER: No issues. Thank you for checking.

ASSISTANT: Welcome, thank you for choosing us.