You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you?

USER: I am William White. Please book a ticket from JFK to DFW to meet my family.

ASSISTANT: May I know your trip dates?

USER: I have planned to travel on 06/03 and 06/05.

ASSISTANT: Ok, please wait a minute.

USER: Ok.

ASSISTANT: Sorry, on these dates you are planning to travel? Actually, on these dates there is no flights available.

USER: Ok, no problem. Thank you.

ASSISTANT: Most welcome.