You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Joseph Lopez here.

ASSISTANT: How can I assist you?

USER: I want to visit the legendary places at Chicago, can you please help me to book a ticket from OAK to ORD?

ASSISTANT: Sure Lopez, can I know the travel dates please?

USER: Ok, my dates of journey is from 04/12 to 04/14.

ASSISTANT: Ok, wait a moment please.

USER: Sure, take your time.

ASSISTANT: Sorry, there are no flights on your dates.

USER: Ok, no problem.

ASSISTANT: Thank you for approaching us.

USER: Thank you for your information.