You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you today?

USER: I am Frank Martinez. I want to book a flight ticket to Houston HOU, help me in booking my flight ticket from Chicago ORD.

ASSISTANT:  Sure, I can help you with that and can you please mention your departure and arrival dates of your journey?

USER: My travelling dates will be May 5th to May 07.

ASSISTANT: Please wait for a minute.

USER: Sure.

ASSISTANT: Sorry, I could not find any flight with your travelling dates.

USER: Its ok, thank you for your effort.

ASSISTANT: Thanks for choosing us, have a great day ahead.