You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Joseph Harris here.

ASSISTANT: How may I guide you today?

USER: Reserve a flight ticket for me that is from IAH to LGA.

ASSISTANT: Sure, I will help you with that. Can you please share your journey dates?

USER: My travelling dates for journey are 03/16 to 03/18.

ASSISTANT: Please wait for a while.

USER: Ok.

ASSISTANT: I am sorry to say that there is no flight found.

USER: Ok, not a problem. Thank you.

ASSISTANT: Thank you for contacting us.